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List of Freshwater Fishes reported from Lao
(landlocked)

n = 601
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Table 1: 575 species currently present in the country/island (endemic, native, introduced, reintroduced);
Table 2: 16 species possibly present in the country/island (stray, questionable);
Table 3: 10 species demonstrated to be absent in the country/island (extirpated, not established, misidentification, error).
Table 4: 601 species reported from the country/island altogether.
Table : 601 .
     
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Family Species Author Info Occurrence Common names Abundance Max length Maturity Remark Photo
Cyprinidae Aaptosyax grypus Rainboth, 1991 Fr native  Pa sanak gnai (Laotian), Pa sanak (Laotian), Sanak (Laotian) fairly common (chances are about 50%) 130 cm SL male/unsexed  Occurs in the middle Mekong River and lower most course of main tributaries (Ref. 43281). Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Apparently restricted to the mainstream of the Mekong River, where it may well be the rarest of the larger fish species (Ref. 9497). According to fishermen from Ban Hang Khone, the appearance of large pa sanak in December is a signal that the November-December migration of pa uhn (Probarbus) has ended (Ref. 9497). Also Ref. 10431, 30857, 37770. 
Gobionidae Abbottina rivularis (Basilewsky, 1855) Fr, Fi introduced   18.90 cm TL male/unsexed  Introduced in the Mekong basin. 
Cobitidae Acanthopsoides delphax Siebert, 1991 Fr native   6.00 cm SL male/unsexed  Occurs in the Mekong basin (Ref. 43281). Found in the lower Xe Bangfai, a tributary of the Mekong basin (Ref. 27732). Also Ref. 30857. 
Cobitidae Acanthopsoides gracilentus (Smith, 1945) Fr native   6.00 cm SL male/unsexed  Occurs in the middle Xe Bangfai, a tributary of the Mekong basin (Ref. 27732). Also Ref. 30857, 43281. 
Cobitidae Acanthopsoides gracilis Fowler, 1934 Fr native   5.40 cm SL male/unsexed  Known from the Mekong basin. Also Ref. 36654.  No picture yet.
Cobitidae Acanthopsoides hapalias Siebert, 1991 Fr native   6.00 cm TL male/unsexed  Known from the Mekong basin (Ref. 43281). Occurs in the lower and middle Xe Bangfai, a tributary of the Mekong basin (Ref. 27732). Also Ref. 30857. 
Cobitidae Acantopsis dialuzona Van Hasselt, 1823 Fr native  Pa it (Laotian)  25.00 cm SL male/unsexed  Known from the Mekong basin (Ref. 4792). Also Ref. 7050, 36654. 
Cobitidae Acantopsis dinema Boyd & Page, 2017 Fr native   11.67 cm SL male/unsexed  Known from the tributaries of the Mekong River draining the Khorat Plateau and Mekong Delta ecoregions (Ref. 116755).  No picture yet.
Cobitidae Acantopsis ioa Boyd & Page, 2017 Fr native  Slender horseface loach (English)  13.20 cm SL male/unsexed  Widely distributed in the mainstem Mekong River. Also occurs in Nam Lik, a large tributary of the Mekong (Ref. 116755).  No picture yet.
Cobitidae Acantopsis rungthipae Boyd, Nithirojpakdee & Page, 2017 Fr native   11.97 cm SL male/unsexed  Known from Mekong River basin (Ref. 116755).  No picture yet.
Acheilognathidae Acheilognathus barbatulus Günther, 1873 Fr native   8.70 cm TL male/unsexed  Known from Nam Ma basin (Houaphan Province, South China Sea slope) and from Nam Ma Yen (Louang Nam Tha Province, Mekong basin). Also Ref. 43281. 
Acheilognathidae Acheilognathus deignani (Smith, 1945) Fr native   5.20 cm SL male/unsexed  Occurs in a tributary of Mekong River at Ban Nam Puat (Ref. 37773). Also Ref. 4792, 94476. 
Acheilognathidae Acheilognathus longibarbatus (Mai, 1978) Fr native   9.20 cm SL male/unsexed  Occurs in the Nam Mat basin (Ref. 43281).  No picture yet.
Acheilognathidae Acheilognathus tonkinensis (Vaillant, 1892) Fr native   12.20 cm TL male/unsexed  Known from Nam Mat basin. 
Soleidae Achiroides leucorhynchos Bleeker, 1851 Fr native   8.00 cm SL male/unsexed   
Soleidae Achiroides melanorhynchus (Bleeker, 1850) Fr questionable   14.00 cm SL male/unsexed  Listed as Achiroides cf. melanorhynchus in Ref. 30857; occurrence needs verification. 
Cyprinidae Acrossocheilus iridescens (Nichols & Pope, 1927) Fr native   29.70 cm SL male/unsexed  Known from Nam Xam and Nam Ma basins. 
Cyprinidae Acrossocheilus xamensis Kottelat, 2000 Fr native   23.53 cm SL male/unsexed  Known only from the Nam Xam basin. Type locality is Houay Tangoua, small stream entering Nam Xam in Ban Houatangoua, Houaphan Prov. (Ref. 36949). Also Ref. 43281.  No picture yet.
Cyprinidae Ageneiogarra theunensis (Kottelat, 1998) Fr native   30.00 cm SL male/unsexed  Occurs in the upper, middle and lower Nam Theun (Ref. 27732). Recorded from Nam Kading to Nam Tha basins (Ref. 43281).  No picture yet.
Akysidae Akysis bilustris Ng, 2011 Fr native   2.53 cm SL male/unsexed   
Akysidae Akysis ephippifer Ng & Kottelat, 1998 Fr native   3.36 cm SL male/unsexed  Known from Xe Kong of the Mekong basin. Also Ref. 52824. 
Akysidae Akysis recavus Ng & Kottelat, 1998 Fr native   4.00 cm SL male/unsexed   
Akysidae Akysis variegatus (Bleeker, 1846) Fr native  Pa khi hia (Laotian)  4.30 cm TL male/unsexed  Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province. Also Ref. 12693. 
Akysidae Akysis varius Ng & Kottelat, 1998 Fr native   4.00 cm SL male/unsexed  Occurs in the Xe Bangfai basin of the Mekong in western Laos. Type locality, Khammouan province (Ref. 30226). Also Ref. 30857. 
Cyprinidae Albulichthys albuloides (Bleeker, 1855) Fr native   30.00 cm SL male/unsexed  Known from the Mekong basin. Also Ref. 7050. 
Cyprinidae Altigena elegans (Kottelat, 1998) Fr native   3.50 cm SL male/unsexed  Occurs in the upper, middle and lower Nam Theun, a tributary of the Mekong basin (Ref. 27732). Found in Nam Kading basin and possibly present in Nam Ngum basin (Ref. 43281).  No picture yet.
Cyprinidae Altigena lippa (Fowler, 1936) Fr native   28.40 cm SL male/unsexed    No picture yet.
Botiidae Ambastaia nigrolineata (Kottelat & Chu, 1987) Fr native   8.00 cm SL male/unsexed  Occurs in the upper Xe Bangfai, a tributary of the Mekong basin (Ref. 27732). Also Ref. 30857, 43281. 
Botiidae Ambastaia sidthimunki (Klausewitz, 1959) Fr native  Pba moo (Laotian)  5.50 cm SL male/unsexed  Found in the Mekong basin (Ref. 43281). Also Ref. 4792, 31466, 50526. 
Amblycipitidae Amblyceps caecutiens Blyth, 1858 Fr native   7.30 cm SL male/unsexed  Presence in the country is expected. Inhabits streams with moderate to swift current, often with gravel to pebble bottom (Ref. 43281).  No picture yet.
Amblycipitidae Amblyceps mangois (Hamilton, 1822) Fr native   12.50 cm SL male/unsexed   
Amblycipitidae Amblyceps serratum Ng & Kottelat, 2000 Fr native   4.53 cm SL male/unsexed  Collected from upriver of Mahaxai from mouth of Nam Phit to about 4 km downriver, Xe Bangfai, Khammouan Prov. and Xe Pon between rapids upstream and downstream of Ban Fuang, Savannakhet Prov. (Ref. 37785).  No picture yet.
Danionidae Amblypharyngodon chulabhornae Vidthayanon & Kottelat, 1990 Fr native   4.00 cm SL male/unsexed  Occurs in the Mekong basin. Also Ref. 30857. 
Cyprinidae Amblyrhynchichthys micracanthus Ng & Kottelat, 2004 Fr native   19.67 cm SL male/unsexed   
Cyprinidae Amblyrhynchichthys truncatus (Bleeker, 1850) Fr native  Dta bo (Laotian), Jon (Laotian), Pa ta po (Laotian), Pba dta jon (Laotian), Pba dta pbo (Laotian), Pba jon (Laotian)  40.00 cm SL male/unsexed  Known from the Mekong basin (Ref. 30857, 4792, 43281). Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Previously very common in the January-February migration at Ban Hang Khone, but it is now uncommon and may be more reduced than most species (Ref. 12369). Museum: Mekong at Ban Hang Khone, just below the Khone Falls, CAS 94272 (Ref. 5515). Becoming locally rare (Ref. 43281). Also Ref. 7050, 37767. 
Anabantidae Anabas testudineus (Bloch, 1792) Fr, Br, Fi native  Pa kheng (Laotian), Pba keng (Laotian)  25.00 cm TL male/unsexed  Occurs in the Mekong basin. Found in the lower and middle Xe Bangfai, and the middle Nam Theun (Ref. 27732) and Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 4792, 30857, 50526. 
Cyprinidae Anematichthys repasson (Bleeker, 1853) Fr native  Da si (Laotian), Dok niew (Laotian), Dta sai (Laotian), Pa doke ngieu (Laotian), Pa khao i thai (Laotian)  28.00 cm SL male/unsexed  Occurs in the Mekong, the middle and lower Xe Bangfai, and the middle and lower Nam Theun (Ref. 27732). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 4792, 2091, 30857, 36654, 43281. 
Anguillidae Anguilla marmorata Quoy & Gaimard, 1824 Fr, Br, Thr native  Pa lai fai fa (Laotian), Pba lat meow (Laotian)  70.00 cm TL male/unsexed ;200 cm TL female  Known from the Mekong basin at Ban Hang Khone, Khong District, Champasak Province (Ref. 37767). Museum: Mekong river near Ban Hang Khone, below Lee Pee waterfalls CAS 96565 (Ref. 5515). Also Ref. 30857, 43281, 56905. 
Gastromyzontidae Annamia normani (Hora, 1931) Fr native  Pa tit hin (Laotian)  7.80 cm SL male/unsexed  Occurs in the upper Xe Bangfai, a tributary of the Mekong basin (Ref. 27732). Also Ref. 4792, 30857, 43281. 
Tetraodontidae Auriglobus modestus (Bleeker, 1850) Fr native  Pa pao luang (Laotian)  10.60 cm SL male/unsexed  Known from the Mekong basin. 
Tetraodontidae Auriglobus nefastus (Roberts, 1982) Fr native   13.00 cm SL male/unsexed  Occurs in the Mekong basin (Ref. 43281). 
Badidae Badis ruber Schreitmüller, 1923 Fr native   5.00 cm SL male/unsexed  Occurs in the Mekong basin (Louang Phabang, Ref. 43281). 
Sisoridae Bagarius bagarius (Hamilton, 1822) Fr misidentification  Pa ke (Laotian)  230 cm TL male/unsexed  Probably referring to Bagarius lica. 
Sisoridae Bagarius lica Volz, 1903 Fr, Fi, Thr native  Pa khe (Laotian), Pa khae (Laotian), Pba kae (Laotian)  200 cm SL male/unsexed  Occurs in the Mekong tributary, the lower and middle Xe Bangfai (Ref. 27732). Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Undertakes upstream migration during the wet season in July-August through Hoo Som Yai at the Great Fault Line on the Mekong River, Champassack Province (Ref. 37771). Reported to migrate during the dry season in December/January in Southern Laos (Ref. 37769). Questionably found in the lower and middle Nam Theun (Ref. 27732). Also Ref. 4833, 30857, 35669, 37767, 43281, 50526. 
Sisoridae Bagarius rutilus Ng & Kottelat, 2000 Fr native   100.00 cm SL male/unsexed  Known from the Nam Xam And Nam Ma basins (Ref. 43281). Also Ref. 37037.  No picture yet.
Sisoridae Bagarius suchus Roberts, 1983 Fr native   70.00 cm SL male/unsexed  Known from the Mekong River (Ref. 43281). Also Ref. 30857, 12693. 
Sisoridae Bagarius vegrandis Ng & Kottelat, 2021 Fr native   22.00 cm SL male/unsexed    No picture yet.
Bagridae Bagrichthys macracanthus (Bleeker, 1854) Fr native  Pa mak khan mak kheu (Laotian), Pa ka theung (Laotian), Pa makahn makehr (Laotian)  25.00 cm SL male/unsexed  Known from the Mekong River (Ref. 30857). Collected from Tha Ngon and Hatsalao (Ref. 4792). Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Occurs in the Mekong mainstream at Hat Village, Muang Khong District (Ref. 37769). Museum: Mekong at Ban Hang Khone, just below Khone Falls, CAS 92487 (Ref. 5515). Also Ref. 37767, 43281. 
Bagridae Bagrichthys macropterus (Bleeker, 1854) Fr native  Pa kouay souk (Laotian), Pa gooay sook (Laotian), Pa makahn makehr (Laotian)  30.00 cm TL male/unsexed  Found in the Mekong River. Collected at Hatsalao (Ref. 4792) and Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). 
Bagridae Bagrichthys obscurus Ng, 1999 Fr native   24.91 cm SL male/unsexed  Known from the Mekong basin (Ref. 43281). Also Ref. 38653. 
Cyprinidae Balantiocheilos melanopterus (Bleeker, 1850) Fr native  Pa pit (Laotian)  35.00 cm SL male/unsexed  Known from the Mekong basin. Also Ref. 4792, 36654. 
Balitoridae Balitora annamitica Kottelat, 1988 Fr native   12.00 cm TL male/unsexed  Known from the Mekong River. 
Balitoridae Balitora kwangsiensis (Fang, 1930) Fr native   12.00 cm TL male/unsexed  Occurs in the Nam Ma basin (Ref. 43281). 
Balitoridae Balitora lancangjiangensis (Zheng, 1980) Fr native   7.10 cm SL male/unsexed  Known from the Mekong basin. Found in the Mekong tributaries: the lower, middle and upper Nam Theun and the upper Xe Bangfai rivers (Ref. 27732). Also Ref. 43281.  No picture yet.
Balitoridae Balitoropsis zollingeri (Bleeker, 1853) Fr native   10.00 cm TL male/unsexed  Occurs in the Mekong basin downriver of Khone Falls (Ref. 43281). 
Cyprinidae Barbichthys laevis (Valenciennes, 1842) Fr native  Pa va hang dam (Laotian)  31.00 cm TL male/unsexed  Known from the Mekong basin (Ref. 30857, 43281). Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Also Ref. 4792, 37767. 
Cyprinidae Barbodes aurotaeniatus (Tirant, 1885) Fr native   9.00 cm TL male/unsexed  Occurs in the middle Xe Bangfai and the middle Nam Theun of the Mekong basin (Ref. 27732). Also Ref. 4792, 30857, 36654, 43281. 
Cyprinidae Barbodes binotatus (Valenciennes, 1842) Fr native   20.00 cm SL male/unsexed  Known from the Mekong River. Also Ref. 4792, 36654. 
Cyprinidae Barbodes rhombeus (Kottelat, 2000) Fr native   6.50 cm SL male/unsexed  Known from the Mekong basin. Also Ref. 36949. 
Cyprinidae Barbodes semifasciolatus (Günther, 1868) Fr native   7.00 cm TL male/unsexed  Occurrence in the Mekong basin in northern Laos probably result from introduction (Ref. 43281). 
Cyprinidae Barbonymus altus (Günther, 1868) Fr, Fi native  Wien fai (Laotian), Pa wien fai (Laotian), Pba wian fai (Laotian) fairly common (chances are about 50%) 25.00 cm TL male/unsexed  Occurs in the Mekong and the lower Xe Bangfai (Ref. 27732). Found below the Mun-Chin River to the Knone Falls (Ref. 37772) and at Hat Village in Muang Khong District (Ref. 37769). Reported to migrate upstream during the dry season in December/January in Southern Laos (Ref. 37769). Recent decline in fisheries attributed to "lee" (large immobile wing traps used in rapids below Lee Pee). Upstream non-reproductive migration occurs in Jan-Feb lasting 1 wk - 10 days and downstream migrations in May-July at night in Ban Hang Khone, just below the great waterfalls of the Mekong River (Ref. 9497). Observed to undergo migration at the fishing village of Ban Wernsonkhram on Don Hat (Hat Island) above the Lee Pee Waterfalls (Ref. 10431). This species is occasionally poisonous, causing vomiting, due to the fruits it has eaten (Ref. 12369). Museum: Mekong, CAS 96270 (near Ban Hang Khone), CAS 93464 (just below Khoné falls) (Ref. 5515). Also Ref. 4792, 9497, 30857, 36654, 37767, 44002, 56905. 
Cyprinidae Barbonymus gonionotus (Bleeker, 1849) Fr, Fi, Aq native  Pa pak (Laotian), Pak (Laotian)  43.00 cm TL male/unsexed  Occurs in the Mekong and the lower Xe Bangfai (Ref. 27732). Known from above Pak Beng to the Khone Falls (Ref. 37772). Museum: Mekong at Ban Hang Khone, just below Khone Falls, CAS 96254 (Ref. 5515). Also Ref. 4792, 30857, 37768, 43281. 
Cyprinidae Barbonymus schwanefeldii (Bleeker, 1854) Fr native  Pa vien fai (Laotian)  35.00 cm SL male/unsexed  Occurs in the Mekong basin. Found in the lower Xe Bangfai river, a tributary of the Mekong (Ref. 27732). Also Ref. 7050, 30857, 36654, 43281. 
Siluridae Belodontichthys truncatus Kottelat & Ng, 1999 Fr, Fi native  Khop (Laotian), Pa khop (Laotian)  60.00 cm SL male/unsexed  Found in the Mekong River drainage (Ref. 38432, 43281). Known from Tha Bo, Pakse and Hatsalao in the Mekong (Ref. 4792). Occurs in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 44002. 
Osphronemidae Betta prima Kottelat, 1994 Fr native   5.00 cm SL male/unsexed  Known from the Mekong basin downriver of Khone Falls (Ref. 43281). 
Osphronemidae Betta smaragdina Ladiges, 1972 Fr native   7.00 cm TL male/unsexed  Found in the Mekong basin (Ref. 43281). 
Osphronemidae Betta splendens Regan, 1910 Fr native   6.50 cm TL male/unsexed  Reported from the Mekong basin (Ref. 4792). Also Ref 30857 (listed as Betta cf. splendens). 
Sciaenidae Boesemania microlepis (Bleeker, 1858) Fr, Br, Fi, Thr native  Pa kouang (Laotian), Pa gooawng (Laotian), Pba gooawng (Laotian)  100.00 cm SL male/unsexed  Known from the Mekong basin (Ref. 43281). Occurs in the Khone Falls (Ref. 37772) and Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee. Reported to migrate upstream during the dry season in January/March in Southern Laos (Ref. 37769). Regarded by Ban Hang Khone fishermen as non-migratory. The present catch in Ban Hang Khone is reportedly only about 10% of what it was in 1970 (Ref. 9497). Becoming locally rare (Ref. 43281). Museum: Mekong at Ban Hang Khone, just below Khone Falls, CAS 94880 (Ref. 5515). Also Ref. 12369, 36654, 37767, 56905. 
Oxudercidae Boleophthalmus boddarti (Pallas, 1770) Fr native   22.00 cm TL male/unsexed   
Danionidae Boraras micros Kottelat & Vidthayanon, 1993 Fr native   1.33 cm SL male/unsexed  Known from the Mekong basin. Also Ref. 30857. 
Danionidae Boraras urophthalmoides (Kottelat, 1991) Fr native   4.00 cm TL male/unsexed   
Soleidae Brachirus harmandi (Sauvage, 1878) Fr native  Pa pe (Laotian)  10.00 cm SL male/unsexed  Occurs in the Mekong basin in the lower Xe Bangfai (Ref. 27732). Also Ref. 4792, 30857, 43281. 
Soleidae Brachirus panoides (Bleeker, 1851) Fr native  Pa pan gnai (Laotian)  20.00 cm TL male/unsexed  Occurs in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 30857 (listed as Euryglossa cf. panoides). 
Soleidae Brachirus siamensis (Sauvage, 1878) Fr native   15.00 cm SL male/unsexed  Occurs in the Mekong basin downstream of Khone Falls (Ref. 43281).  No picture yet.
Gobiidae Brachygobius mekongensis Larson & Vidthayanon, 2000 Fr native   1.75 cm SL male/unsexed  Occurs in the Mekong River (Ref. 38652). Type locality: Xe Champhon, between bridge at Muang Kengkok and about 4 km upstream, Xe Biang Hiang Basin, Savannakhet (Ref. 43716). 
Cyprinidae Carassius auratus (Linnaeus, 1758) Fr native   48.00 cm TL male/unsexed  Introduced in the Mekong basin in northern Laos. Also found in the Nam Ma basin. 
Cyprinidae Carassius praecipuus Kottelat, 2017 Fr native   6.20 cm SL male/unsexed  Known only from upper Nam Chat, Mekong drainage in the hills of central Laos (Ref. 116770).  No picture yet.
Cyprinidae Catlocarpio siamensis Boulenger, 1898 Fr, Fi, Thr native  Pa kaho (Laotian) scarce (very unlikely) 300 cm TL male/unsexed  Known from the Mekong basin (Ref. 43281). A migratory species occurring in the Khoné Falls (Ref. 37772). Found in Ban Hang Khone, middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Enters flooded forest on Don Khone, just below the great waterfalls (Ref. 9497). Becoming very rare (Ref. 43281). Also Ref. 4792, 36654, 30857, 37770, 56905. 
Ariidae Cephalocassis borneensis (Bleeker, 1851) Fr native  Pa khat ok (Laotian)  30.00 cm SL male/unsexed  Known from the Mekong basin downriver of Khone Falls (Ref. 43281). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Museum: Mekong, Ban Hang Khone, just below Khone falls, CAS 94790; below Khone falls, CAS 96724 (Ref. 5515). Also Ref. 30857. 
Cyprinidae Ceratogarra cambodgiensis (Tirant, 1883) Fr native  Pba gaw hin (Laotian)  24.00 cm TL male/unsexed  Known from the Mekong basin in Nam Theun and the middle and upper Xe Bangfai (Ref. 27732); Xe Kong watershed, Xe Namnoy (Ref. 128869). Museum: Mekong river at Ban Hang Khone, just below Khone falls, CAS 94937 (Ref. 5515). Also Ref. 4792, 30857, 36654, 36949, 50526. 
Cyprinidae Ceratogarra fasciacauda (Fowler, 1937) Fr native  Pa kikko (Laotian)  11.00 cm SL male/unsexed  Occurs in the Mekong River. Found in the lower Xe Bangfai (Ref. 27732) and in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 4792, 30857, 43281. 
Siluridae Ceratoglanis pachynema Ng, 1999 Fr native   28.00 cm SL male/unsexed  Known from the Mekong basin (Ref. 43281). 
Channidae Channa gachua (Hamilton, 1822) Fr native  Pa kan (Laotian)  32.90 cm TL male/unsexed  Occurs in the Mekong tributaries, the lower and middle Xe Bangfai, and the middle Nam Theun (Ref. 27732). Also Ref. 4792, 30857, 43281, 50526. 
Channidae Channa lucius (Cuvier, 1831) Fr native  Pa tion (Laotian)  53.00 cm TL male/unsexed  Known from the Mekong basin. Also Ref. 4792, 36654. 
Channidae Channa marulius (Hamilton, 1822) Fr native  Pa kouan (Laotian), Pa gooan (Laotian), Pba gooa (Laotian)  183 cm TL male/unsexed  Recorded from the lower Mekong basin (Ref. 9497). Occurs in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Enters flooded forest (Ref. 9497). Also Ref. 30857 (listed as Channa cf. marulius). Also Ref. 36654. 
Channidae Channa melasoma (Bleeker, 1851) Fr native   30.00 cm SL male/unsexed  Found in the Mekong basin. Also Ref. 4792, 36654. 
Channidae Channa micropeltes (Cuvier, 1831) Fr, Fi native  Pa meng phou (Laotian), Pa do (Laotian)  130 cm SL male/unsexed  Known from the Mekong basin (Ref. 43281). Found in the lower Xe Bangfai, tributary of the Mekong basin (Ref. 27732), around Pak Beng to the Khone Falls (Ref. 37772) and Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 4792, 30857, 56905. 
Channidae Channa orientalis Bloch & Schneider, 1801 Fr native  Pa kang (Laotian), Pa kan (Laotian)  33.00 cm TL male/unsexed  Occurs in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Museum: Mekong below Khone falls, CAS 96770 (Ref. 5515). Also Ref. 7050. 
Channidae Channa striata (Bloch, 1793) Fr, Fi, Thr native  Pa kaw (Laotian), Pa kho (Laotian), Pba kaw (Laotian)  100.00 cm SL male/unsexed  Known from the Mekong basin. Found in the middle Xe Bangfai and the middle Nam Theun rivers (Ref. 27732) and Ban Hang Khone, about 3 km below the fall line of the great waterfalls of the Mekong river system at Lee Pee (Ref. 9497). Recorded from the Khone Falls (Ref. 37772). Migrates into the flooded forest on Don Khone and Don Saddam to forage (Ref. 37772). Also Ref. 2686, 4792, 30857, 37767, 37772, 43281, 50526, 56905. 
Chaudhuriidae Chaudhuria caudata Annandale, 1918 Fr native   6.00 cm TL male/unsexed  Known from the Mekong basin (Ref. 43281). Chaudhuria fusipinnis and C. caudata occur in syntopy at the type locality of C. fusipinnis: confluence of Nam Leuk and Nam Ngang (Ref. 36949). 
Chaudhuriidae Chaudhuria fusipinnis Kottelat & Britz, 2000 Fr native   4.50 cm SL male/unsexed  Known only from the Nam Mang basin (Mekong). Also Ref. 43281.  No picture yet.
Notopteridae Chitala blanci (d'Aubenton, 1965) Fr, Fi, Thr native  Dtong gai (Laotian), Pa tong kai (Laotian), Pba dtawng lai (Laotian), Tong gai (Laotian)  120 cm SL male/unsexed  Found in the mainstream of the Mekong River (Ref. 7431) where there is fast current and rocky substrates (Ref. 9497). Also known from a tributary of the Mekong in the middle Xe Bangfai basin near Mahaxai (Ref. 27732) and from Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong River system at Lee Pee (Ref. 9497). According to Ban Hang Khone fishermen this species enters the flooded forest in July-October and feeds on fish, shrimps, crabs and insects (Ref. 9497). Museum: Mekong at Ban Hang Khone just below the Khone falls, CAS 94784 (Ref. 5515). Also Ref. 30857, 36654, 37767, 37769. 
Notopteridae Chitala lopis (Bleeker, 1851) Fr extirpated   150 cm SL male/unsexed  Known from the Mekong basin (Ref. 43281). Also Ref. 12693. 
Notopteridae Chitala ornata (Gray, 1831) Fr, Fi native  Dtong kwai (Laotian), Pa tong keua (Laotian), Pa tong khouay (Laotian), Pa tong khua (Laotian)  100.00 cm SL male/unsexed  Occurs in the Mekong basin (Ref. 43281). Found in the middle Xe Bangfai basin, a tributary of the Mekong (Ref. 27732) and in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). According to Ban Hang Khone fishermen this species enters the flooded forest in July-October and feeds on fish, shrimps, crabs and insects (Ref. 9497). Also Ref. 30857, 37767, 37770. 
Cyprinidae Cirrhinus cirrhosus (Bloch, 1795) Fr, Br, Fi introduced  Pa nang chan (Laotian)  100.00 cm SL male/unsexed  Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 4832, 8984, 26920, 30857, 43281, 56905. 
Cyprinidae Cirrhinus jullieni Sauvage, 1878 Fr, Br, Fi native  Pa dok ngieu pha (Laotian), Pa soi (Laotian)  20.00 cm SL male/unsexed  Known from the Mekong basin in southernmost Laos below Khone Falls (Ref. 33488). Museum: Mekong river at Ban Hang Khone, just below Khone falls, CAS 93258 (Ref. 5515). Also Ref. 4792, 37767, 30857. 
Cyprinidae Cirrhinus microlepis Sauvage, 1878 Fr, Fi, Aq, Thr native  Pawn (Laotian), Pa pawn (Laotian), Pa phone (Laotian), Pba pawn (Laotian)  65.00 cm SL male/unsexed  Occurs in the Mekong basin. A migratory species known from above Pak Beng to the Khoné Falls (Ref. 37772). Found in the lower Xe Bangfai (Ref. 27732) and Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Inhabits riffle, deep slow reaches of the Mekong basin at Muang Khong (Ref. 37769). Undertakes non-reproductive upstream migration in December-March and downstream migration in June-July at Hat Village, Muang Khong District (Ref. 37769). Observed also to undergo migration at the fishing village of Ban Wernsonkhram on Don Hat (Hat Island) above the Lee Pee Waterfalls (Ref. 10431). Also migrates downstream during the wet season in July-August through Hoo Som Yai at the Great Fault Line on the Mekong River, Champassack Province (Ref. 37771). Moves into flooded forest on Don Khone and Don Saddam to forage (Ref. 37772). From Xayabouri in Laos to Chiang Saen in Thailand, it undertakes upstream migrations from March to August. One of the most important fishes at the Khone Falls during the dry season from January to March, when it migrates upstream. Has been artificially induced to spawn in Pakse in Champassak Province (Ref. 37770). Also Ref. 4792, 10431, 30857, 36654, 37767. 
Cyprinidae Cirrhinus molitorella (Valenciennes, 1844) Fr, Fi, Aq, Thr native  Geng (Laotian), Pa geng (Laotian), Pa keng (Laotian), Pba geng (Laotian)  55.00 cm TL male/unsexed  Occurs in the Mekong, the lower and middle Xe Bangfai, and the lower Nam Theun basins (Ref. 27732). Found in Ban Hang Khone in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Inhabits rapids, slow deep reaches of the Mekong basin at Hat Village, Muang Khong District and makes an upstream non-reproductive migration in December-February and downstream migration in July-August (Ref. 37769 ). Observed to undergo migration and fished heavily at the fishing village of Ban Wernsonkhram on Don Hat (Hat Island) above the Lee Pee Waterfalls (Ref. 10431). Interviews with fishermen strongly suggest that population in Southern Lao Mekong mainstream has declined some 20 or so years ago (Ref. 37769 ). Aquacultural stock reportedly has been introduced from China into the Mekong basin in Laos (Ref. 33488). Also Ref. 4792, 30857, 43281. 
Clariidae Clarias batrachus (Linnaeus, 1758) Fr, Br, Fi misidentification  Pa douk (Laotian)  47.00 cm TL male/unsexed  Occurs in the Mekong basin (Ref. 43281). Found in the middle Xe Bangfai, and the middle Nam Theun (Ref. 27732, 2686), Pak Beng to the Mun-Chin River (Ref. 37772) and Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also collected from Tha Ngon, Tha Bo and Hatsalao in the Mekong basin (Ref. 4792). Found in paddies, swamps and canals at Vientiane, Savannakhet and Pakse (Ref. 4792). In Khammouan Province, movement into small streams is triggered by the first heavy rains at the end of the dry season (Ref. 37770). Spends the dry season living around rocks in the main river (Ref. 37770). Also Ref. 30857, 56905. 
Clariidae Clarias fuscus (Lacepède, 1803) Fr native   24.50 cm SL male/unsexed   
Clariidae Clarias gariepinus (Burchell, 1822) Fr introduced   170 cm TL male/unsexed  Introduced in 1980 from Viet Nam for aquaculture reasons (Ref. 58867). Also Ref. 30857, 43281. 
Clariidae Clarias macrocephalus Günther, 1864 Fr, Br, Fi, Aq native  Pa douk (Laotian) occasional (usually not seen) 120 cm TL male/unsexed  Found in the Mekong River. Occurs above the Pak Beng to the Khone Falls (Ref. 37772). In Laos, this fish is considered to be better and more nourishing than Clarias batrachus (Ref 2686). Also Ref. 2686, 4792, 43281. 
Clariidae Clarias meladerma Bleeker, 1846 Fr native   35.00 cm SL male/unsexed  Known from the Mekong basin (Ref. 43281). 
Clariidae Clarias serniosus Ng & Kottelat, 2014 Fr native   16.10 cm SL male/unsexed  Found only in the Xe Pian drainage (tributary of the Xe Kong, itself a tributary of the Mekong) flowing from the Bolavens Plateau in southern Laos (Ref. 97697).  No picture yet.
Ehiravidae Clupeichthys aesarnensis Wongratana, 1983 Fr native   7.00 cm SL male/unsexed  Known from the Mekong basin in the lower Xe Bangfai River (Ref. 27732). Also Ref. 30857. 
Ehiravidae Clupeichthys goniognathus Bleeker, 1855 Fr native   12.00 cm TL male/unsexed   
Ehiravidae Clupeoides borneensis Bleeker, 1851 Fr native   8.00 cm SL male/unsexed  Occurs in the Mekong and its tributary, the lower Xe Bangfai River (Ref. 27732). Also Ref. 7050. 
Ailiidae Clupisoma sinense (Huang, 1981) Fr native   31.00 cm SL male/unsexed  Known from the Mekong River (Ref. 30857, 43281). 
Cobitidae Cobitis laoensis (Sauvage, 1878) Fr native   10.60 cm SL male/unsexed  Originally described from Laos on the basis of a single specimen collected aroung 1870, but the species has not been reported again from the country. Possibly this is a specimen from another area, with erroneous locality data (Ref. 43281).  No picture yet.
Engraulidae Coilia lindmani Bleeker, 1857 Fr native   20.00 cm SL male/unsexed   
Cyprinidae Cosmochilus harmandi Sauvage, 1878 Fr, Fi native  Mak ban (Laotian), Pa mak ban (Laotian), Pa tiok (Laotian)  100.00 cm TL male/unsexed  Known from the Mekong River (Ref. 30857, 43281). Its numbers have declined in the Khone Falls (Ref. 37772). Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Observed to undergo migration at the fishing village of Ban Wernsonkhram on Don Hat (Hat Island) above the Lee Pee Waterfalls (Ref. 10431). Reported to migrate upstream during the dry season in December/January in Southern Laos (Ref. 37769). Museum: Mekong at Ban Hang Khone, just below Khone falls, CAS 94891 (Ref. 5515). Also Ref. 4792, 36654, 37767, 56905. 
Cyprinidae Crossocheilus atrilimes Kottelat, 2000 Fr native   16.40 cm TL male/unsexed  Known from the Mekong basin. Type locality: Nam Mang at Keng Nam Mang (rapids) about 6 km upstream of Ban Hatkhai, Vientiane Prov. (Ref. 36949). Also Ref. 43281. 
Cyprinidae Crossocheilus cobitis (Bleeker, 1854) Fr native   14.80 cm TL male/unsexed  Known from the Mekong basin (Ref. 43281). Also Ref. 4792, 30857. 
Cyprinidae Crossocheilus oblongus Kuhl & Van Hasselt, 1823 Fr native  Pa khang lai noi (Laotian)  16.00 cm SL male/unsexed  Occurs in the Mekong and the lower Xe Bangfai (Ref. 27732). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 4792, 30857. 
Cyprinidae Crossocheilus reticulatus (Fowler, 1934) Fr native  Pa tok thoi (Laotian), Pa kiang (Laotian), Pba kee kom (Laotian)  17.00 cm SL male/unsexed  Occurs in the Mekong and the lower and middle Xe Bangfai (Ref. 27732). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Museum: Mekong at Ban Hang Khone, just below Khone falls CAS 94289 (Ref. 5515). Also Ref. 4792, 30857, 36654, 43281, 50526. 
Xenocyprididae Ctenopharyngodon idella (Valenciennes, 1844) Fr, Fi, Aq not established  Pa kin gnia (Laotian)  150 cm TL male/unsexed  Used for koy pa or is eaten raw with nam pa sauce or nam padek and scraps of hot chili pepper. Does not breed in natural water bodies (Ref. 58867). Also Ref. 43281, 56905. 
Cyprinidae Cyclocheilichthys apogon (Valenciennes, 1842) Fr native  Pa dok ngieu (Laotian), Pba dawk ngiew (Laotian)  28.70 cm TL male/unsexed  Found in the Mekong River (Ref. 30857) at Ban Hang Khone in Khong District, Champasak Province (Ref. 37767). Also Ref. 7050. 
Cyprinidae Cyclocheilichthys armatus (Valenciennes, 1842) Fr, Fi native  Dok niew 1 (Laotian), Pa dok ngieu khao (Laotian), Pa tiok (Laotian)  23.00 cm SL male/unsexed  Found in the lower Xe Bangfai basins, a tributary of the Mekong basin (Ref. 27732). Collected from Tha Ngon, Hatdokkeo, Tha Bo, SIthan Tay, Pakse (Ref. 4792). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 7050, 30857, 43281. 
Cyprinidae Cyclocheilichthys enoplos (Bleeker, 1849) Fr, Fi, Thr native  Jork (Laotian), Pa chok (Laotian), Pa choke (Laotian), Pa jawk (Laotian), Pa johk (Laotian), Pa tiok (Laotian), Pba johk (Laotian)  74.00 cm SL male/unsexed  Recorded from the Mekong basin. Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). At Ban Hang Khone its migrations formerly were exceeded in magnitude only by those of pa soi and pa dtaep (Ref. 9497). Observed to undergo migration at the fishing village of Ban Wernsonkhram on Don Hat (Hat Island) above the Lee Pee Waterfalls (Ref. 10431). Above the Khone Falls, fishes migrate upstream during April-September which are dominated by adults. These are probably spawning migrations as mature fishes bearing eggs were observed in Xayabouri Province from April to September (Ref. 37770). Also migrates upstream during dry season in December/January at Hat Village, Muang Khong District (Ref. 37769). Its numbers have declined in the Khone Falls (Ref. 37772). Also Ref. 4792, 7050, 36654, 37767, 56905. 
Cyprinidae Cyclocheilichthys furcatus Sontirat, 1989 Fr native   60.00 cm SL male/unsexed  Known from the Mekong River. Also Ref. 12693, 30857. 
Cyprinidae Cyclocheilichthys heteronema (Bleeker, 1854) Fr native   12.00 cm SL male/unsexed  Occurs in the Mekong basin. Also Ref. 12693. 
Cyprinidae Cyclocheilichthys lagleri Sontirat, 1989 Fr native   15.00 cm SL male/unsexed  Also Ref. 30857. 
Cynoglossidae Cynoglossus microlepis (Bleeker, 1851) Fr native  Pa lin ma (Laotian)  32.50 cm SL male/unsexed  Known from the Mekong basin (Ref. 43281). Occurs in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 30857. 
Cyprinidae Cyprinus carpio Linnaeus, 1758 Fr, Br, Fi, Aq introduced  Nai (Laotian), Pa nai (Laotian), Pba ni (Laotian)  120 cm TL male/unsexed  Known from the Mekong basin from above Pak Beng to the Khoné Falls (Ref. 37772). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Undertakes reproductive and trophic/dispersal upstream migration during the wet season in May-July through Hoo Som Yai at the Great Fault Line on the Mekong River, Champassack Province (Ref. 37771). Also Ref. 185, 8984, 12228, 26920, 30857, 50526, 56905, 58867. 
Cyprinidae Cyprinus rubrofuscus Lacepède, 1803 Fr native   28.00 cm SL male/unsexed  Known from Xiangkhouang and Louang Phabang (Ref. 43281). 
Danionidae Danio albolineatus (Blyth, 1860) Fr native   9.58 cm TL male/unsexed  Known from the Mekong River. Recorded from Nam Xi below Kuang Xi waterfall, upstream of Ban Thapen (Ref. 37788). Also Ref. 7050, 30857. 
Danionidae Danio roseus Fang & Kottelat, 2000 Fr native   3.65 cm SL male/unsexed  Known from the Mekong basin in Louang Phabang Province, northern Laos (Ref. 37789). 
Lobotidae Datnioides microlepis Bleeker, 1854 Fr native  Pa seua (Laotian), Pa soua (Laotian)  55.00 cm TL male/unsexed  Occurs in the Mekong basin. Found in Ban Hang Khone, about 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Does not migrate but enters the flooded forest (Ref. 9497). Also Ref. 4792, 7050, 36654. 
Lobotidae Datnioides pulcher (Kottelat, 1998) Fr native   40.00 cm SL male/unsexed  Occurs in the Mekong basin (Ref. 43281). Becoming very rare locally, or even extirpated, because of its high value as a food fish and for the aquarium trade (Ref. 43281). 
Lobotidae Datnioides undecimradiatus (Roberts & Kottelat, 1994) Fr native  Pa seua (Laotian), Pba seua (Laotian)  40.00 cm SL male/unsexed  Occurs in the Mekong and the lower and middle Xe Bangfai (Ref. 27732). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Museum: Mekong River, downstream from Lee Pee (or Khone) waterfalls, ZRC 35114 (Holotype). Also Refs. 10425, 30857, 43281, 44002. 
Cyprinidae Decorus lemassoni (Pellegrin & Chevey, 1936) Fr native   30.00 cm SL male/unsexed  Known from Nam Ma basin. Also Ref. 44416.  No picture yet.
Zenarchopteridae Dermogenys pusilla Kuhl & van Hasselt, 1823 Fr questionable   16.10 cm TL male/unsexed  Museum: Mekong below Khone falls, CAS 93262 (Ref. 5515). Records from Laos (Ref. 30857, 5515) are outside distributional range and need further confirmation. 
Zenarchopteridae Dermogenys siamensis Fowler, 1934 Fr native   4.00 cm SL male/unsexed ;6.00 cm SL female  Occurs in the Mekong basin (Ref. 43281). 
Danionidae Devario acrostomus (Fang & Kottelat, 1999) Fr native   11.30 cm TL male/unsexed  Known from Nam Leuk, Mekong basin in Vientiane Province. Collected or observed in the Nam Leuk mainstream (upstream and downstream of the falls ) and in several small forest streams (Ref. 37788). Also Ref. 43281. 
Danionidae Devario aequipinnatus (McClelland, 1839) Fr native   15.00 cm TL male/unsexed   
Danionidae Devario apopyris (Fang & Kottelat, 1999) Fr native   3.83 cm SL male/unsexed  Occurs in a stream near Ban Nakbon, Nam Youan watershed of the Mekong basin, northern Laos. Also Ref. 43281.  No picture yet.
Danionidae Devario chrysotaeniatus (Chu, 1981) Fr native   7.10 cm SL male/unsexed  Found in the Nam Youan watershed of the Mekong in Louang Namtha Province, northern Laos. The Nam Youan River drains from Laos to China where it enters the Nan La He River. Also Ref. 43281. 
Danionidae Devario fangfangae (Kottelat, 2000) Fr native   6.81 cm SL male/unsexed  Presently known only from the Nam Kading basin, but expected to occur in other basins in central Laos (Ref. 36949).  No picture yet.
Danionidae Devario gibber (Kottelat, 2000) Fr native   6.50 cm SL male/unsexed  Known from the Xe Kong and Xe Don basins of the Mekong. Expected to occur in other basins in southern Laos (Ref.36949).  No picture yet.
Danionidae Devario laoensis (Pellegrin & Fang, 1940) Fr native   8.00 cm TL male/unsexed  Known from several localities in the upper Mekong drainage. Found in Ban Nam Khueng, Huey Nam Puat (tributary of Mekong) at Nam Puat and Nam Xi below Kuang waterfall, upstream of Ban Thapen. Also Ref. 4792, 37787. 
Danionidae Devario leptos (Fang & Kottelat, 1999) Fr native   5.19 cm SL male/unsexed  Known from the Nam Tha watershed in Louang Namtha Province, and Nam Beng watershed in Oudomxai Province, Mekong basin, northern Laos (Ref. 37788), and Nam Khan basin (Ref. 43281).  No picture yet.
Danionidae Devario regina (Fowler, 1934) Fr native   10.80 cm TL male/unsexed  Occurs in the Mekong basin at Houei Nhang River near Pakse. 
Danionidae Devario salmonatus (Kottelat, 2000) Fr native   4.47 cm SL male/unsexed  Presently known only from the Xe Nam Noy on the Bolaven Plateau, above the falls (Ref. 36949).  No picture yet.
Tetraodontidae Dichotomyctere fluviatilis (Hamilton, 1822) Fr native   17.00 cm TL male/unsexed  Occurs in the Mekong basin. 
Cyprinidae Discherodontus ashmeadi (Fowler, 1937) Fr native  Pba sawk jan (Laotian)  13.60 cm SL male/unsexed  Occurs in the Mekong in the middle Xe Bangfai (Ref. 27732). Also Ref. 4792, 30857. 
Cyprinidae Discherodontus parvus (Wu & Lin, 1977) Fr native   6.70 cm SL male/unsexed  Known from Nam Youan basin and Xishuangbanna (Ref. 43281).  No picture yet.
Syngnathidae Doryichthys boaja (Bleeker, 1850) Fr native   41.00 cm SL male/unsexed  Known from the Mekong basin (Ref. 43281). 
Syngnathidae Doryichthys contiguus Kottelat, 2000 Fr native   10.98 cm SL male/unsexed  Known from the Mekong basin. Material has been collected in the Nam Mang, Xe Bangfai, Xe Bang Hiang and Xe Kong basins (Ref. 36949). Also Ref. 43281. 
Syngnathidae Doryichthys deokhatoides (Bleeker, 1854) Fr native   18.50 cm SL male/unsexed  Occurs in the Mekong and the middle Xe Bangfai (Ref. 27732). 
Cyprinidae Epalzeorhynchos frenatum (Fowler, 1934) Fr native  Pa tout hin (Laotian)  15.00 cm TL male/unsexed  Occurs in the Mekong and the lower Xe Bangfai (Ref. 27732). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 4792, 30857, 36654, 43281. 
Cyprinidae Epalzeorhynchos munense (Smith, 1934) Fr native   9.30 cm SL male/unsexed  Known from the middle Xe Bangfai, a tributary of the Mekong basin (Ref. 27732). 
Danionidae Esomus longimanus (Lunel, 1881) Fr native  Pa sieu (Laotian)  8.00 cm SL male/unsexed  Occurs in the Mekong basin at Tha Ngon, Tha Bo and Sithan Tay (Ref. 4792). Also Ref. 36654. 
Danionidae Esomus metallicus Ahl, 1923 Fr native  Pa sieu houa gnen (Laotian), Pa sieu (Laotian)  7.50 cm SL male/unsexed  Occurs in the Mekong River. Found in the middle Xe Bangfai River (Ref. 27732), Tha Ngon, Tha Bo and Hatsalao in the Mekong basin (Ref. 4792) and Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 30857, 36654. 
Cyprinidae Folifer brevifilis (Peters, 1881) Fr native   40.50 cm TL male/unsexed   
Poeciliidae Gambusia affinis (Baird & Girard, 1853) Fr introduced   5.10 cm TL male/unsexed ;7.00 cm TL female  Found in Louang Nam Tha Province (Ref. 43281). 
Cyprinidae Garra cyclostomata Mai, 1978 Fr native   15.00 cm SL male/unsexed  Occurs in northeastern Laos (Ref. 43281).  No picture yet.
Cyprinidae Garra cyrano Kottelat, 2000 Fr native   10.30 cm SL male/unsexed  Presently known only from the Middle Nam Mang basin (Ref. 36949). Also Ref. 43281.  No picture yet.
Cyprinidae Garra fuliginosa Fowler, 1934 Fr native   18.00 cm SL male/unsexed  Known from the Mekong River (Ref. 43281). Also Ref. 30857. 
Gobiidae Glossogobius aureus Akihito & Meguro, 1975 Fr native   25.00 cm SL male/unsexed  Found in the Mekong basin downriver of Khone Falls (Ref. 43281). 
Gobiidae Glossogobius giuris (Hamilton, 1822) Fr native  Pa boo (Laotian)  50.00 cm SL male/unsexed  Not found above the Lee Pee Waterfalls suggesting that the falls act as barrier between them and the rest of the Mekong River. Listed as Glossogobius cf. giuris in Ref. 30857. 
Gobiidae Glossogobius koragensis Herre, 1935 Fr native  Pa bou khao (Laotian)  25.00 cm male/unsexed  Recorded from Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Listed as Glossogobius cf. koragensis in Ref. 30857. Also Ref. 12693. 
Sisoridae Glyptothorax forabilis Ng & Kottelat, 2017 Fr native   8.96 cm SL male/unsexed  Type locality of Glyptothorax forabilis, Champasak Province, Pakxong District, Bolaven Plateau, Xe Katam, about 2 km upstream of bridge on road from Pakxong to Attapeu. Known from the Xe Nam Noy drainage on the Bolaven Plateau in southern Laos (Ref. 117341).  No picture yet.
Sisoridae Glyptothorax fuscus Fowler, 1934 Fr native   12.10 cm SL male/unsexed  Known from the Mekong basin (Ref. 43281). Also Ref. 30857. 
Sisoridae Glyptothorax honghensis Li, 1984 Fr native   8.80 cm SL male/unsexed  Known from NE Laos.  No picture yet.
Sisoridae Glyptothorax interspinalum (Mai, 1978) Fr native   10.55 cm SL male/unsexed  Known from Nam Ma basin (Ref. 43281). 
Sisoridae Glyptothorax lampris Fowler, 1934 Fr native   12.10 cm SL male/unsexed  Occurs in the middle and upper Xe Bangfai, a tributary of the Mekong (Ref. 27732). Listed as Glyptothorax cf. lampris in Ref. 30857. Also Ref. 36654. 
Sisoridae Glyptothorax laosensis Fowler, 1934 Fr native   10.80 cm SL male/unsexed  Occurs in the middle and upper Xe Bangfai, a tributary of the Mekong (Ref. 27732). Listed as Glyptothorax cf. laosensis in Ref. 30857. Also Ref. 43281. 
Sisoridae Glyptothorax macromaculatus Li, 1984 Fr native   16.08 cm SL male/unsexed  Occurs in the Nam Theun basin, a tributary of the Mekong (Ref. 27732). Also Ref. 43281. 
Sisoridae Glyptothorax major (Boulenger, 1894) Fr native   14.40 cm TL male/unsexed   
Sisoridae Glyptothorax porrectus Ng & Kottelat, 2017 Fr native   11.94 cm SL male/unsexed  Type locality of Glyptothorax porrectus, Champasak Province, Pakxong District, Bolaven Plateau, Xe Nam Noy at bridge downstream of Xe Pian–Xe Nam Noy dam site. Known from southern Laos in Xe Nam Noy drainage in the Bolaven Plateau (Ref. 117341).  No picture yet.
Sisoridae Glyptothorax trilineatus Blyth, 1860 Fr native   30.00 cm TL male/unsexed  Known from the Mekong basin at Houei Nhang River near Pakse. Also Ref. 41236. 
Sisoridae Glyptothorax zanaensis Wu, He & Chu, 1981 Fr native   11.51 cm SL male/unsexed  Occurs in the middle Nam Theun, a tributary of the Mekong (Ref. 27732). Also Ref. 43281. 
Gobiidae Gobiopterus chuno (Hamilton, 1822) Fr native   3.00 cm SL male/unsexed  Found in the Mekong basin (Ref. 43281). 
Gyrinocheilidae Gyrinocheilus aymonieri (Tirant, 1883) Fr native  Pa ko (Laotian), Pba gaw (Laotian)  28.00 cm SL male/unsexed  Occurs in the middle Xe Bangfai, a tributary of the Mekong basin (Ref. 27732). Also Ref. 4792, 13074, 30857, 36654, 43281, 50526. 
Gyrinocheilidae Gyrinocheilus pennocki (Fowler, 1937) Fr, Fi native  Ko (Laotian), Pa gaw (Laotian), Pa ko (Laotian), Pba gaw (Laotian), Pba ko (Laotian)  28.00 cm SL male/unsexed  Found in the Mekong basin (Ref. 13074). Occurs in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Inhabits riffle/rapids of the Mekong basin in Muang Khong District (Ref. 37769). Undertakes an upstream trophic migration to rocky sections of the mainstream in the Muang Khong area from around early to mid-January until February where it grazes on filamentous algae growing on rock surfaces (Ref. 37769). Fish landings gradually diminish from about the end of February and by April only a small number of fish are being landed; it reappears following an increase of water level at the start of the monsoon season but then almost completely disappears after a few days until the following January (Ref. 37769). Observed to undergo migration and fished heavily at the fishing village of Ban Wernsonkhram on Don Hat (Hat Island) above the Lee Pee Waterfalls (Ref. 10431). Museum; Mekong river FB Gypen_u1.jpg; Mekong river at Ban Hang Khone, just below Khone falls, CAS 93266 (Ref. 5515). Also Ref. 4792, 30857, 44002, 56905. 
Cyprinidae Hampala dispar Smith, 1934 Fr, Fi native  Sout 1 (Laotian), Pa sou (Laotian)  35.00 cm SL male/unsexed  Occurs in the Mekong basin. Found in the lower and middle Xe Bangfai (Ref. 27732) and Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Collected from Luang Prabang, Tah Ngon, Vientiane, Tha Bo, Sithan Tay, Hatsalao, Bang Lieng (Ref. 4792). Museum: Mekong at Ban Hang Khone, CAS 94927 (Ref. 5515). Also Ref. 30857, 36654, 37767. 
Cyprinidae Hampala macrolepidota Kuhl & Van Hasselt, 1823 Fr, Fi native  Sout (Laotian), Pa soot (Laotian), Pa sou (Laotian), Pa sout (Laotian), Pba soot (Laotian)  70.00 cm SL male/unsexed  Occurs in the Mekong basin. Found in the lower and middle Xe Bangfai river (Ref. 27732), Khone Falls (Ref. 37772) and Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls at Lee Pee (Ref. 9497). A migratory species (Ref. 37772). Enters flooded forest on Don Khone, just below the great waterfalls (Ref. 9497). Museum: Mekong, CAS 93264 (Below Khone Falls); CAS 94888 (Ban Hang Khone, just below Khone Falls) (Ref. 5515). Also Refs. 2686, 30857, 36654, 37767, 37769, 45536, 50526, 56905. 
Pangasiidae Helicophagus leptorhynchus Ng & Kottelat, 2000 Fr native   47.20 cm SL male/unsexed  Known from the Mekong basin (Ref. 43281). Also Ref. 39387 
Pangasiidae Helicophagus waandersii Bleeker, 1858 Fr, Fi native  Noo (Laotian), Pa noo (Laotian), Pa nou (Laotian), Pba noo (Laotian)  70.00 cm TL male/unsexed  Known from Mekong River (Ref. 30857). Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Collected from Tha Ngon, Tha Bo and Hatsalao of the Mekong basin (Ref. 4792). Enters flooded forest on Don Khone, just below the great waterfalls (Ref. 9497). Observed to undergo migration at the fishing village of Ban Wernsonkhram on Don Hat (Hat Island) above the Lee Pee Waterfalls (Ref. 10431). Also undertakes upstream migration during the wet season in May-July through Hoo Som Yai at the Great Fault Line on the Mekong River, Champassack Province (Ref. 37771). Reported to migrate upstream during the dry season in December/February in Southern Laos (Ref. 37769). The most dominant fish in catches at Don Khong (Khong Island), just above Lee Pee Waterfalls from 29 October through 11 December 1993 (Ref. 10431). Caught all year long, but particularly abundant at the end of the year according to Khong Island fishermen (Ref. 10431). Museum: Mekong at Ban Hang Khone, just below Khone falls, CAS 94890 (Ref. 5515). Also Ref. 36654, 37769, 37767, 44002, 56905. 
Ariidae Hemiarius stormii (Bleeker, 1858) Fr native  Pa khat ok sop lem (Laotian), Pa kaht oak (Laotian)  50.00 cm TL male/unsexed  Known from the Mekong basin downriver of Khone Falls (Ref. 43281). Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Museum: Mekong river at Ban Hang Khone, just below Khone Falls, CAS 96570 (Ref. 5515). Also Ref. 37767, 30857. 
Ariidae Hemiarius verrucosus (Ng, 2003) Fr native   80.00 cm TL male/unsexed  Found in the Mekong River and possibly in the lower Bang Pakong (Ref. 58022).  No picture yet.
Bagridae Hemibagrus filamentus (Fang & Chaux, 1949) Fr, Br native   50.00 cm TL male/unsexed  Known from the Mekong basin. Also Ref. 43281. 
Bagridae Hemibagrus guttatus (Lacepède, 1803) Fr native   73.10 cm SL male/unsexed  Found in Nam Xam and Nam Ma basins (Ref. 43281). 
Bagridae Hemibagrus microphthalmus (Day, 1877) Fr, Br, Fi misidentification  Pa kung (Laotian), Pba keung (Laotian) abundant (always seen in some numbers) 150 cm NG male/unsexed  Records refer to Hemibagrus wyckioides (Ref. 43281). Reported from the Mekong mainstream at Hat Village, Muang Khong District (Ref. 37769). Undertakes upstream migration during the wet season in July-August through Hoo Som Yai at the Great Fault Line on the Mekong River, Champassack Province (Ref. 37771). Caught throughout the year and probably is the most abundant large catfish in Ban Hang Khone. Enters flooded forest in July-October during the months of high water. A number of very small individuals were observed in June-July indicating that it breeds locally. Feeds on shrimps, fish and crabs. Caught on hooks, "bet ken" or "bet piak" (individual hooks or setlines) (Ref. 9497). Also Ref.9497, 56905. 
Bagridae Hemibagrus nemurus (Valenciennes, 1840) Fr, Br, Fi native  Kot (Laotian), Pa goht (Laotian), Pa kot (Laotian), Pa kot leuang (Laotian), Pba goht (Laotian), Pba goht leuang (Laotian)  65.00 cm SL male/unsexed  Occurs in the Mekong and the lower and middle Xe Bangfai (Ref. 27732). Found in the Mekong mainstream at Hat Village, Muang Khong District (Ref. 37769). Collected from Tha Ngon, Vientiane, Tha Bo, Sithan Tay, Pakse and Hatsalao (Ref. 4792) and Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Enters flooded forest on Don Khone, just below the great waterfalls at Lee Pee (Ref. 9497). Undertakes reproductive upstream migration during the wet season in May-July through Hoo Som Yai at the Great Fault Line on the Mekong River, Champassack Province (Ref. 37771). Also Ref. 4792, 30857, 36654, 44002, 50526, 56905. 
Bagridae Hemibagrus planiceps (Valenciennes, 1840) Fr native   33.50 cm TL male/unsexed  Known from the Mekong basin. 
Bagridae Hemibagrus pluriradiatus (Vaillant, 1892) Fr native   21.60 cm SL male/unsexed  Found in Nam Xam basin (Ref. 43281). 
Bagridae Hemibagrus wyckii (Bleeker, 1858) Fr native  Pa kot mo (Laotian), Pa goht mahw (Laotian), Pa kheung (Laotian)  90.00 cm TL male/unsexed  Known from the Mekong River (Ref. 30857). Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Undertakes reproductive upstream migration during the wet season in May-June through Hoo Som Yai at the Great Fault Line on the Mekong River, Champassack Province (Ref. 37771). Also Ref. 4792, 37767, 50526. 
Bagridae Hemibagrus wyckioides (Fang & Chaux, 1949) Fr, Thr native  Pa kheung (Laotian)  130 cm TL male/unsexed  Occurs in the Mekong basin. Found in the lower and middle Nam Theun basin, tributary of the Mekong (Ref. 27732) and Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Museum: Mekong at Ban Hang Khone, just below Khone falls, CAS 94877 (Ref. 5515). Also Ref. 30857, 44002, 56905. 
Gobionidae Hemibarbus labeo (Pallas, 1776) Fr introduced   67.00 cm TL male/unsexed  Recorded from Mekong basin from Bokeo Province. Occurrence is apparently the result of introduction, either in Laos, or more likely upriver in Mekong basin in China (Ref. 37786). Also Ref. 43281. 
Gobionidae Hemibarbus maculatus Bleeker, 1871 Fr introduced   47.00 cm TL male/unsexed ;34.30 cm TL female  Occurrence in the Mekong tributaries in northern Laos apparently results from introductions upriver in China (Ref. 43281). A potential serious competitor and threat for the native benthic fishes (Ref. 43281). 
Xenocyprididae Hemiculterella macrolepis Chen, 1989 Fr native   13.50 cm SL male/unsexed  Known from the tributaries of the Mekong in the upper Xe Bangfai and the middle and upper Nam Theun basins (Ref. 27732). Also Ref. 43281.  No picture yet.
Balitoridae Hemimyzon confluens Kottelat, 2000 Fr native   4.65 cm SL male/unsexed  Presently known only from the upper Nam Ngum of the Mekong basin (Ref. 36949). Also Ref. 43281.  No picture yet.
Balitoridae Hemimyzon khonensis Kottelat, 2000 Fr native   5.07 cm SL male/unsexed  Only known from immediately downriver of Khone Falls of the Mekong basin (Ref. 36949). Also Ref. 42935, 43281.  No picture yet.
Balitoridae Hemimyzon papilio Kottelat, 1998 Fr native   5.92 cm SL male/unsexed  Occurs in the upper, middle and lower Nam Theun, a tributary of the Mekong (Ref. 27732). Also Ref. 42935, 43281. 
Balitoridae Hemimyzon pengi (Huang, 1982) Fr native   5.90 cm SL male/unsexed  Occurs in the Mekong basin (Ref. 43281).  No picture yet.
Siluridae Hemisilurus heterorhynchus (Bleeker, 1854) Fr, Thr native  Pa dan deng (Laotian)  80.00 cm TL male/unsexed  Found in the Mekong basin at Hatsalao. Also Ref. 36654, 56905. 
Siluridae Hemisilurus mekongensis Bornbusch & Lundberg, 1989 Fr, Fi native  Nang deng (Laotian), Pa nang daeng (Laotian), Pa nang deng (Laotian), Pba nang deng (Laotian)  80.00 cm TL male/unsexed  Known from Mekong River (Ref. 43281). Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497) and in the Mekong mainstream at Hat Village, Muang Khong District (Ref. 37769). Enters flooded forest on Don Khone, just below the great waterfalls (Ref. 9497). Undertakes upstream migration during the wet season in May-June through Hoo Som Yai at the Great Fault Line on the Mekong River, Champassack Province (Ref. 37771). Also Ref. 37767, 30857, 56905. 
Dasyatidae Hemitrygon laosensis (Roberts & Karnasuta, 1987) Fr, Thr native  Fa hang (Laotian), Pa fa hang (Laotian), Pa fa lai (Laotian)  62.00 cm WD male/unsexed  Known from the Mekong basin (Ref. 9840, 27732) in the Nakornpanom Province (Ref. 32444) and in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Champasak Province (Ref. 37767). Reported also to occur in the Mekong above the great waterfalls (Ref. 9497). Fishermen at Ban Hang Khone recognize only one large species of pa fa hang or stingray, attaining 30 kg or more (presumably Dasyatis laosensis) (Ref. 9497). Museum: Mekong river at Ban Hang Khone, just below Khone Falls, CAS 93987 (Ref. 5515). Also Ref. 9840, 12693, 30857, 56905. 
Cyprinidae Henicorhynchus caudimaculatus (Fowler, 1934) Fr native  Pa soi lai (Laotian), Pa soi (Laotian)  26.60 cm TL male/unsexed  Known from the Mekong basin (Ref. 123185); in the lower and middle Xe Bangfai (Ref. 27732); in Ban Hang Khone in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Museum: Mekong at Ban Hang Khone, just below Khone falls, CAS 94791 (Ref. 5515). Also Ref. 30857, 50526. 
Cyprinidae Henicorhynchus entmema (Fowler, 1934) Fr, Fi native  Pa soi houa lem (Laotian), Pba soi hang leuang (Laotian), Pba soi hooa lem (Laotian), Pba soi hua lem (Laotian)  15.00 cm SL male/unsexed  Recorded from the Mekong basin (Ref. 33488). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Undertakes downstream migration during the wet season in late May/June-July through Hoo Som Yai at the Great Fault Line on the Mekong River, Champassack Province (Ref. 37771). Reported to migrate upstream during the dry season in December/March in Southern Laos (Ref. 37769). In terms of absolute numbers, it almost certainly is the single most abundant fish species below the Khone Waterfalls during the two migratory periods, December-February and May-July. It is the lead species in almost all of the major migrations of cyprinids moving up the Mekong in December-January. The lead migrators find their way upstream by trial and error. During migration, it is the only species that vocalizes to call conspecifics to migrate to the spawning grounds (Ref. 12369). Vocalizations last for about one month until all of the C. lobatus have migrated south according to villagers from Ban Don Tolatee, Ban Hang Khone and Ban Ta Kahm (Ref. 12369). Museum: Mekong, CAS 94936 (Ban Hang Khone); CAS 96189 (below Khone falls); CAS 94942 (Ban Hang Khone just below Khone falls) (Ref. 5515). Seasonally one of the most abundant species (Ref. 43281). Also Ref. 30857, 37771, 44002, 50526, 56905. 
Cyprinidae Henicorhynchus ornatipinnis (Roberts, 1997) Fr native  Red-finned mud carp (English)  9.50 cm SL male/unsexed  Occurs in the Mekong basin (Ref. 43281). 
Cyprinidae Henicorhynchus siamensis (Sauvage, 1881) Fr, Fi native  Pa soi houa po (Laotian), Pa mohk (Laotian), Pa soi (Laotian), Pba mohk (Laotian)  20.00 cm SL male/unsexed  Occurs in the Mekong and the lower and middle Xe Bangfai (Ref. 27732). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Undertakes upstream and dowstream migrations during the wet season in June-July through Hoo Som Yai at the Great Fault Line on the Mekong River, Champassack Province (Ref. 37771). Reported to migrate upstream during the dry season in December/March in Southern Laos (Ref. 37769). From Xayabouri in Laos to Chiang Khong in Thailand, this species is reported to migrate upstream from March to July, first by juveniles, later by adults (Ref. 37770). Museum: Mekong river, CAS 93270 (Ban Hang Khone, below Lee Pee waterfalls); CAS 94931 (Ban Hang Khone); CAS 96204, 94279 (Ban Hang Khone just below Khone falls) (Ref. 5515). Also Ref. 4792, 10431, 30857, 33488, 36654, 37770, 43281, 44002, 56905. 
Heteropneustidae Heteropneustes fossilis (Bloch, 1794) Fr questionable   41.20 cm TL male/unsexed  Outside distributional range, likely a misidentification of H. fossilis. Known from the Mekong basin (Ref. 4792). Also Ref. 4537, 4833, 41236, 43640. 
Heteropneustidae Heteropneustes kemratensis (Fowler, 1937) Fr native   27.00 cm SL male/unsexed  Occurs in the Mekong basin (Ref. 43281). 
Dorosomatidae Hilsa kelee (Cuvier, 1829) Fr native  Pa mak pang (Laotian)  35.00 cm TL male/unsexed  Found in the Mekong basin. 
Balitoridae Homaloptera confuzona Kottelat, 2000 Fr native   6.80 cm SL male/unsexed  Known from the Mekong basin downriver of Khone Falls (Ref. 36949). Also Ref. 43281. 
Balitoridae Homaloptera orthogoniata Vaillant, 1902 Fr native  Pba dtit hin (Laotian)  13.00 cm SL male/unsexed   
Balitoridae Homalopteroides smithi (Hora, 1932) Fr native  Pa tit hin (Laotian), Pba dtit hin (Laotian)  9.80 cm TL male/unsexed  Known from the Mekong tributaries in the upper, middle, and lower Xe Bangfai and Nam Theun (Ref. 27732). Listed as Homaloptera cf. smithi in Ref. 30857. Also Ref. 4792, 36654, 43281, 50526. 
Balitoridae Homalopteroides tweediei (Herre, 1940) Fr native   4.00 cm SL male/unsexed  Known from the Mekong basin downriver of Khone Falls (Ref. 43281). Also Ref. 30857. 
Xenocyprididae Hypophthalmichthys molitrix (Valenciennes, 1844) Fr not established   120 cm TL male/unsexed   
Xenocyprididae Hypophthalmichthys nobilis (Richardson, 1845) Fr, Fi introduced   146 cm SL male/unsexed  Also Ref. 8984, 26920, 56905. 
Cyprinidae Hypsibarbus lagleri Rainboth, 1996 Fr native  Pa pak pay (Laotian)  40.00 cm SL male/unsexed  Known from the Mekong River (Ref. 30857, 43281) at Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 37768. 
Cyprinidae Hypsibarbus malcolmi (Smith, 1945) Fr, Fi native  Pa khao lan (Laotian), Pa pak kom (Laotian), Pa pak nouat (Laotian)  50.00 cm SL male/unsexed  Known from the Mekong River (Ref. 30857, 43281) at Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 37768, 44002. 
Cyprinidae Hypsibarbus pierrei (Sauvage, 1880) Fr native  Pa pak ta leuang (Laotian), Pa pak khao (Laotian)  36.90 cm TL male/unsexed  Found in the Mekong River (Ref. 30857, 43281). Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Also Ref. 4792, 37767. 
Cyprinidae Hypsibarbus vernayi (Norman, 1925) Fr native   30.00 cm SL male/unsexed  Known from the Mekong in the lower and middle Xe Bangfai, and the lower and middle Nam Theun (Ref. 27732). Also Ref. 37768, 43281. 
Cyprinidae Hypsibarbus wetmorei (Smith, 1931) Fr native  Pa pak thong kham (Laotian), Pa pak gohm (Laotian), Pa pak thong leuang (Laotian)  46.00 cm TL male/unsexed  Known from Mekong River (Ref. 30857, 43281). Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Undergoes upstream reproductive migration, mainly at night, in November and December in the Khone Falls. Reported to migrate upstream during the dry season in December/January in Southern Laos (Ref. 37769). Also Ref. 4792, 37767, 37768, 37772. 
Pristigasteridae Ilisha megaloptera (Swainson, 1838) Fr native   36.50 cm SL male/unsexed   
Cyprinidae Incisilabeo behri (Fowler, 1937) Fr, Fi native  Wa na nor (Laotian), Pa va ho kham (Laotian), Pa wa nah nuk (Laotian), Pba wa kum (Laotian), Pba wa na nor (Laotian)  60.00 cm TL male/unsexed  Occurs in the Mekong basin. Collected from Khong Falls (Ref. 4792). Inhabits riffles, slow deep reaches of the Mekong basin at Muang Khong District (Ref. 37769 ). Undertakes upstream non-reproductive migration from December-March/April and downstream migration in June-July at Hat Village, Muang Khong District (Ref. 37769 ). Also migrates dowstream during the wet season in July-August through Hoo Som Yai at the Great Fault Line on the Mekong River, Champassack Province (Ref. 37771). Observed to undergo migration and fished heavily at the fishing village of Ban Wernsonkhram on Don Hat (Hat Island) above the Lee Pee Waterfalls (Ref. 10431). Upstream the Khone Falls, this species starts its upstream migration in the dry season from February to May and continues in the beginning of the rainy season. This may represent two separate migrations, a dry season non-reproductive migration of smaller fish and an early rainy season migration of larger fish in spawning condition (Ref. 37770). Also Ref. 30857, 37767, 56905. 
Indostomidae Indostomus paradoxus Prashad & Mukerji, 1929 Fr questionable   3.00 cm SL male/unsexed  Listed as Indostomus cf. paradoxus in Ref. 30857; occurrence needs verification. 
Indostomidae Indostomus spinosus Britz & Kottelat, 1999 Fr native   3.00 cm SL male/unsexed  Found in the Mekong basin at Bolikhamsai Province (Ref. 38647). 
Siluridae Kryptopterus bicirrhis (Valenciennes, 1840) Fr native  Pa pi kai (Laotian)  15.00 cm SL male/unsexed  Occurs in the lower Xe Bangfai, a tributary of the Mekong (Ref. 27732). Collected from Tha Ngon, Tha Bo, Sai Fong, Sithan Tay and Hatsalao in the Mekong basin (Ref. 4792). Listed as Kryptopterus cf. bicirrhis in Ref. 30857. Also Ref. 12041, 36654, 43281. 
Siluridae Kryptopterus cheveyi Durand, 1940 Fr native   35.00 cm TL male/unsexed  Occurs in the Mekong tributary, the lower Xe Bangfai (Ref. 27732). Listed as Kryptopterus cf. cheveyi in Ref. 30857. Also Ref. 43281, 50582. 
Siluridae Kryptopterus dissitus Ng, 2001 Fr native   17.60 cm SL male/unsexed  Type locality, Mekong River at Ban Hang Khone, just downstream from Khone falls, Champasak Province.  No picture yet.
Siluridae Kryptopterus geminus Ng, 2003 Fr, Fi native  Pa peek gai (Laotian)  17.06 cm SL male/unsexed  Known from the Mekong River drainage (Ref. 50583). Found in the lower and middle Xe Bangfai, a tributary of the Mekong (Ref. 27732). Recorded from the Khone Falls (Ref. 37772). Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497), Tha Ngon, Tha Bo, Sai Fong and Sithan Tay of the Mekong basin (Ref. 4792). Museum: Mekong at Ban Hang Khone, just below Khone falls, CAS 94760 (Ref. 5515). Also Ref. 2091, 30857, 36654, 43281, 56905. 
Siluridae Kryptopterus limpok (Bleeker, 1852) Fr native   26.00 cm SL male/unsexed  Known from the Mekong basin (Ref. 43281). Listed as Kryptopterus cf. limpok in Ref. 30857. 
Siluridae Kryptopterus schilbeides (Bleeker, 1858) Fr native   12.00 cm TL male/unsexed  Reported from the Mekong basin (Ref. 4792). Listed as Kryptopterus cf. schilbeides in Ref. 30857. 
Cyprinidae Labeo barbatulus (Sauvage, 1878) Fr native  Pba idtoo (Laotian)  30.00 cm SL male/unsexed  Occurs in the Mekong basin (Ref. 43281). 
Cyprinidae Labeo catla (Hamilton, 1822) Fr, Fi, Aq not established   182 cm TL male/unsexed  Also Ref. 56905. 
Cyprinidae Labeo chrysophekadion (Bleeker, 1849) Fr, Fi, Aq native  Phia (Laotian), Pa phia (Laotian), Pa pia (Laotian), Pba pia (Laotian)  90.00 cm TL male/unsexed  Occurs in the Mekong basin. Found in the lower and middle Xe Bangfai (Ref. 27732) and Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Enters flooded forest on Don Khone, just below the great waterfalls (Ref. 9497). According to local people in Kinnak market, southern Laos the species appears in reproductive condition in June and July (Ref. 10431). Undertakes upstream migration from March to August (Ref. 37770). Known to migrate into tributaries, small streams and canals and migration commences at the onset of the rainy season or when the water starts rising (Ref. 37770). Also reported to migrate upstream during the dry season in December/March in Southern Laos (Ref. 37769). Also Ref. 4792, 7050, 30857, 36654, 37767. 
Cyprinidae Labeo dyocheilus (McClelland, 1839) Fr, Fi native  Pa va (Laotian)  90.00 cm TL male/unsexed  Known from the Mekong basin. A migratory species that occurs below the Mun-Chin River to the Khone Falls (Ref. 37772). Also Ref. 36654, 56905. 
Cyprinidae Labeo erythropterus Valenciennes, 1842 Fr native  Wa sooang (Laotian), Pa va (Laotian), Pa va souang (Laotian)  70.00 cm SL male/unsexed  Reported from the Mekong basin at Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). 
Cyprinidae Labeo pierrei (Sauvage, 1880) Fr native  Pba sooang (Laotian)  80.00 cm SL male/unsexed  Occurs in the Mekong basin (Ref. 43281). Also Ref. 36654, 50526. 
Cyprinidae Labeo rohita (Hamilton, 1822) Fr, Fi, Aq not established   200 cm TL male/unsexed  Has not been reported to breed in natural water bodies (Ref. 58867). Also Ref. 4823, 8984, 26920, 30857, 56905. 
Cyprinidae Labeo yunnanensis Chaudhuri, 1911 Fr native   49.00 cm SL male/unsexed  Occurs in the Mekong and the middle Xe Bangfai (Ref. 27732). 
Cyprinidae Labiobarbus leptocheilus (Valenciennes, 1842) Fr, Fi native  Pa lang khon (Laotian), Pa khoui lam (Laotian), Pa lang kohn (Laotian), Pa soi (Laotian), Pba pboot (Laotian)  30.00 cm SL male/unsexed  Occurs in the Mekong and the lower and middle Xe Bangfai (Ref. 27732). Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Undertakes upstream and downstream migrations during the wet season in June-July through Hoo Som Yai at the Great Fault Line on the Mekong River, Champassack Province (Ref. 37771). Reported to migrate upstream during the dry season in December/March in Southern Laos (Ref. 37769). Museum: Mekong at Ban Hang Khone, just below Khone falls, CAS 94789 (Ref. 5515). Also Ref. 7424, 10421, 30857, 36654, 37767, 43281, 56905. 
Cyprinidae Labiobarbus lineatus (Sauvage, 1878) Fr native   15.50 cm TL male/unsexed  Tye locality, rapids of Stung-Strang [= Stung Treng, Mekong basin] (Ref. 46206). 
Cyprinidae Labiobarbus siamensis (Sauvage, 1881) Fr native   22.00 cm TL male/unsexed  Known from the Mekong basin (Ref. 7424). Also Ref. 30857, 43281. 
Ailiidae Laides hexanema (Bleeker, 1852) Fr, Fi questionable  Pa gnone thong (Laotian), Pba nyawn (Laotian)  16.50 cm TL male/unsexed  Outside distributional range; likely a misidentification of L. longibarbis. Reported from the Mekong (Ref. 4792). Collected from Pak Suong, Luang Prabang, Tha Ngon, Tha Bo, Sai Fong, Sithan Tay and Hatsalao of the Mekong basin (Ref. 4792). Also found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 30857. 
Ailiidae Laides longibarbis (Fowler, 1934) Fr native   14.20 cm SL male/unsexed  Museum: Mekong River shoulder, Vientiane, CMK 7974 (5.86 cm SL) (Ref. 39209). Also Ref. 27732. 
Cyprinidae Laocypris hispida Kottelat, 2000 Fr native   5.30 cm SL male/unsexed  Occurs in the Nam San (tributary of Nam Ngum) and Nam Mang basins (Ref. 43281). Type locality, tributary of Nam San, Houay Sala Yai, Saisomboun Special Zone (Ref. 36949).  No picture yet.
Danionidae Laubuka caeruleostigmata Smith, 1931 Fr native  Pa khi pagnat (Laotian)  7.00 cm SL male/unsexed  Occurs in the Mekong River (Ref. 30857, 43281). Found in Ban Hang Khone in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). 
Danionidae Laubuka laubuca (Hamilton, 1822) Fr native   10.54 cm TL male/unsexed  Known from the Mekong basin. Also Ref. 4792, 30857. 
Tetraodontidae Leiodon cutcutia (Hamilton, 1822) Fr native  Pa pao (Laotian)  15.00 cm TL male/unsexed  Recorded from the Mekong basin. 
Cobitidae Lepidocephalichthys berdmorei (Blyth, 1860) Fr native   8.00 cm SL male/unsexed  Occurs in the Mekong basin (Ref. 43281). 
Cobitidae Lepidocephalichthys furcatus (de Beaufort, 1933) Fr native   5.00 cm SL male/unsexed  Found in the Mekong basin (Ref. 43281).  No picture yet.
Cobitidae Lepidocephalichthys hasselti (Valenciennes, 1846) Fr native   6.00 cm SL male/unsexed  Known from the Mekong River. Also Ref. 4792, 7050, 30857. 
Cobitidae Lepidocephalichthys kranos Havird & Page, 2010 Fr native   3.31 cm SL male/unsexed ;4.36 cm SL female    No picture yet.
Leptobarbidae Leptobarbus hoevenii (Bleeker, 1851) Fr, Fi native  Pa phong (Laotian), Pa phong long (Laotian), Pa pohng (Laotian)  100.00 cm SL male/unsexed  Known from the Mekong River. A migratory species occurring at the Khoné Falls (Ref. 37772). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Inedible, eating this fish reportedly induces nausea & vomiting. The poison comes from Hydnocarpus fruits (mak gabao & mak ngooan) on which it feeds. Dorsal musculature eaten as lap (raw meat) marinated in vinegar & pepper (Ref. 9497). According to Ban Hang Khone fishermen, this species enters the flooded forest in July-September, feeds heavily on fallen fruit and attains a maximum weight of about 10 kg (Ref. 9497). Also Ref. 4792, 30857, 36654, 56905. 
Cyprinidae Lobocheilos cryptopogon (Fowler, 1935) Fr native   15.00 cm TL male/unsexed  Occurs in the Mekong basin (Ref. 4792). Museum: Mekong at Ban Hang Khone, just below Khone falls, CAS 94791 (Ref. 5515). 
Cyprinidae Lobocheilos davisi (Fowler, 1937) Fr native   9.00 cm TL male/unsexed  Reported from the Mekong basin. 
Cyprinidae Lobocheilos delacouri (Pellegrin & Fang, 1940) Fr native   12.00 cm SL male/unsexed  Known from the Mekong basin. 
Cyprinidae Lobocheilos gracilis (Fowler, 1937) Fr native  common (usually seen) 24.00 cm TL male/unsexed  Known from the Mekong (Ref. 4792). Common in the upper Mekong River (Ref. 12693). 
Cyprinidae Lobocheilos melanotaenia (Fowler, 1935) Fr, Fi native  Pa khiang khang lai (Laotian), Pa kiang (Laotian), Pa soi (Laotian), Pba kiang kang lai (Laotian)  20.00 cm SL male/unsexed  Occurs in the Mekong and the middle Xe Bangfai (Ref. 27732). Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Migrates with pa soi in January-February and again in June-July; according to Ban Hang Khone fishermen this species enters the flooded forest in July-October and feeds on kai hin (filamentous algae) (Ref. 9497). Also undertakes upstream and downstream migrations during the wet season in June-July through Hoo Som Yai at the Great Fault Line on the Mekong River, Champassack Province (Ref. 37771). Reported to migrate upstream during the dry season in December/March in Southern Laos (Ref. 37769). Also Ref. 4792, 30857, 37767, 43281, 50526, 56905. 
Cyprinidae Lobocheilos rhabdoura (Fowler, 1934) Fr native   22.00 cm SL male/unsexed  Occurs in the Mekong River. Also Ref. 36654. 
Xenocyprididae Longiculter siahi Fowler, 1937 Fr native   20.00 cm SL male/unsexed  Known from the Mekong River. Also Ref. 36654. 
Cyprinidae Luciocyprinus striolatus Cui & Chu, 1986 Fr native   200 cm SL male/unsexed  Found in the Mekong River. Occurs in the lower Nam Theun (Ref. 27732). Reported by fishermen in Ban Thabak to be more frequent in Nam Gnouan than in Nam Theun (Ref. 27732). Also Ref. 30857, 43281. 
Danionidae Luciosoma bleekeri Steindachner, 1878 Fr, Thr native  Pa mak vai (Laotian), Pa sieu ao (Laotian), Pba pbawn (Laotian)  25.00 cm SL male/unsexed  Known from the Mekong basin. Collected from Nam Ngum dam site, Tha Ngon, Tha Bo, Sai Fong, Sithan Tay, Pakse and Hatsalao in the Mekong basin (Ref. 4792) and Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 30857, 36654, 56905. 
Danionidae Luciosoma setigerum (Valenciennes, 1842) Fr native  Pa sieu ao (Laotian), Pba pbawm (Laotian)  26.00 cm SL male/unsexed  Occurs in the Mekong River (Ref. 43281). Collected from Nam Ngum dam site and Tha Ngon in the Mekong basin (Ref. 4792). ,Museum: Mekong river at Ban Hang Khone, just below Khone falls, CAS 94567 (Ref. 5515). Also Ref. 30857. 
Engraulidae Lycothrissa crocodilus (Bleeker, 1850) Fr, Br, Fi native  Pa mak chan (Laotian), Pa hang pah (Laotian), Pa maeo (Laotian)  30.00 cm SL male/unsexed  Known from the Mekong basin downstream of Khone Falls (Ref. 43281). Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Museum: Mekong at Ban Hang Khone, just below Khone falls, CAS 94786 (Ref. 5515). Also Ref. 30857, 37767. 
Xenocyprididae Macrochirichthys macrochirus (Valenciennes, 1844) Fr native  Pa hang pha (Laotian), Pa hang fa (Laotian)  100.00 cm TL male/unsexed  Found in the Mekong basin. Occurs in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 2686, 4792, 7050, 30857, 36654, 45563. 
Mastacembelidae Macrognathus aculeatus (Bloch, 1786) Fr native  Pa lot (Laotian)  38.00 cm TL male/unsexed   
Mastacembelidae Macrognathus maculatus (Cuvier, 1832) Fr native   28.00 cm TL male/unsexed   
Mastacembelidae Macrognathus semiocellatus Roberts, 1986 Fr native  Pba loht (Laotian)  19.20 cm SL male/unsexed  Occurs in the lower Xe Bangfai, a tributary of the Mekong (Ref. 27732). Also Ref. 39392, 43281, 50526. 
Mastacembelidae Macrognathus siamensis (Günther, 1861) Fr native  Pa lot (Laotian), Pa laht (Laotian), Pba loht (Laotian)  30.00 cm SL male/unsexed  Occurs in the Mekong basin (Ref. 43281). Found in the middle Xe Bangfai (Ref. 27732) and Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Enters flooded forest on Don Khone, just below the great waterfalls (Ref. 9497). Museum: Mekong, CAS 94928 (Ban Hang Khone); CAS 97091 (Ban Hang Khone, just below Khone falls); CAS 93337 (Huay Nam Ngam & Mekong mainstream near That Phanom); CAS 97064 (near Chiang Khan) (Ref. 5515). Also Ref. 30857, 36654, 37767, 50526. 
Mastacembelidae Macrognathus taeniagaster (Fowler, 1935) Fr native   22.00 cm TL male/unsexed   
Osphronemidae Macropodus opercularis (Linnaeus, 1758) Fr native   6.70 cm SL male/unsexed  Known from the Nam Ngum basin, a tributary to the Mekong and rivers Ma and Ca, draining to the Gulf of Tonkin in North Vietnam. Probably the existence in River Nam gum is partly the result of introductions (Ref. 42924). Also Ref. 43281. 
Mastacembelidae Mastacembelus armatus (Lacepède, 1800) Fr, Br, Fi native  Pa lat (Laotian), Pa loht (Laotian), Pba laht (Laotian)  90.00 cm TL male/unsexed  Known from the Mekong basin (Ref. 43281). Occurs in the lower, middle and upper Xe Bangfai, and the lower and middle Nam Theun basins (Ref. 27732). Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Enters flooded forest on Don Khone, just below the great waterfalls (Ref. 9497). Museum: Mekong at Ban Hang Khone, just below Khone falls, CAS 94889 (Ref. 5515). Also Ref. 30857, 37767, 37770, 50526. 
Mastacembelidae Mastacembelus erythrotaenia Bleeker, 1850 Fr native   100.00 cm TL male/unsexed   
Mastacembelidae Mastacembelus favus Hora, 1924 Fr native  Pa lat (Laotian)  70.00 cm SL male/unsexed  Known from the Mekong River. Also Ref. 4792. 
Cyprinidae Mekongina erythrospila Fowler, 1937 Fr, Fi native  Saee (Laotian), Pa sa i (Laotian), Pa sa-ee (Laotian), Pa wa (Laotian), Pba sa-ee (Laotian), Pba saee (Laotian)  45.00 cm SL male/unsexed  Occurs in the Mekong basin. Found in the middle Xe Bangfai, and the lower Nam Theun basins (Ref. 27732), and in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Collected from Tha Ngon, Sithan Tay, Hatsalao (Ref. 4792). Caught mainly in the deeper slower channels of the Muang Khong area (Mekong) and appears to avoid shallow rocky areas (Ref. 37769 ). Undertakes upstream non-reproductive migration in the Mekong mainstream at Hat Village, Muang Khong District from December to March/April (Ref. 37769 ). Observed to undergo migration and fished heavily at the fishing village of Ban Wernsonkhram on Don Hat (Hat Island) above the Lee Pee Waterfalls (Ref. 10431). Reported to migrate upstream from Pak Lay in Laos to Chiang Khong in Thailand between March and May, which starts when the first heavy rains of the monsoon season occur or when the river water color changes from relatively clear to reddish or brown. Also reported to make downstream migration from Pak Lay in October-November (Ref. 37770). Undertake upstream migration in Xe Done River between December and March (Ref. 37770). Also Ref. 30857, 36654, 37767, 43281, 50526, 56905. 
Xenocyprididae Metzia bounthobi Shibukawa, Phousavanh, Phongsa & Iwata, 2012 Fr native   6.10 cm SL male/unsexed  Found in Ou River basin (a tributary of the Mekong) in Phongsaly and Luang Prabang provinces of northern Laos (Ref. 93140).  No picture yet.
Xenocyprididae Metzia lineata (Pellegrin, 1907) Fr introduced   10.00 cm SL male/unsexed  Spread to northern Laos. 
Siluridae Micronema hexapterus (Bleeker, 1851) Fr questionable   24.00 cm TL male/unsexed  Listed as Kryptopterus cf. hexapterus in Ref. 30857; occurrence needs verification. 
Siluridae Micronema moorei (Smith, 1945) Fr questionable   24.00 cm TL male/unsexed  Known from Mekong. Listed as Kryptopterus cf. moorei in Ref. 30857; occurrence needs verification. 
Gobionidae Microphysogobio labeoides (Nichols & Pope, 1927) Fr native   9.20 cm SL male/unsexed  Known from Nam Mat and Nam Ma basins (Ref. 43281). 
Cobitidae Misgurnus anguillicaudatus (Cantor, 1842) Fr native   28.00 cm SL male/unsexed  Occurs in the middle Nam Theun of the Mekong basin and Nam Ma basin (Ref. 43281). Possibly introduced. Also Ref. 27732. 
Synbranchidae Monopterus albus (Zuiew, 1793) Fr native  Ian (Laotian), I'en (Laotian), Pa lai (Laotian)  100.00 cm SL male/unsexed  Occurs in the Mekong basin (Ref. 43281). Found in the middle Xe Bangfai (Ref. 27732) and Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 2686, 4792, 30857. 
Cyprinidae Mystacoleucus atridorsalis Fowler, 1937 Fr native  Pa lang ko (Laotian)  8.00 cm SL male/unsexed  Occurs in the Mekong and its tributary, the lower Xe Bangfai (Ref. 27732). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 4792, 30857, 36949, 43281. 
Cyprinidae Mystacoleucus chilopterus Fowler, 1935 Fr native   11.00 cm TL male/unsexed  Occurs in the Mekong River. 
Cyprinidae Mystacoleucus ectypus Kottelat, 2000 Fr native   8.00 cm SL male/unsexed  Known from the Mekong basin in central and southern Laos (Ref. 36949). 
Cyprinidae Mystacoleucus greenwayi Pellegrin & Fang, 1940 Fr native   7.30 cm SL male/unsexed  Occurs in the middle Xe Bangfai of the Mekong basin (Ref. 27732). Listed as Mystacoleucus cf. greenwayi in Ref. 30857. Also Ref. 4792, 43281. 
Cyprinidae Mystacoleucus lepturus Huang, 1979 Fr native   9.20 cm SL male/unsexed  Occurs in the Mekong River. 
Cyprinidae Mystacoleucus marginatus (Valenciennes, 1842) Fr native  Pa lang ko (Laotian)  20.00 cm TL male/unsexed  Occurs in the Mekong basin. Known from the lower, middle and upper Xe Bangfai, and the lower and middle Nam Theun basins (Ref. 27732). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Listed as Mystacoleucus cf. marginatus in Ref. 30857. Also Ref. 4792, 43281. 
Bagridae Mystus albolineatus Roberts, 1994 Fr native   35.00 cm SL male/unsexed  Known from the Mekong River (Ref. 43281). Also Ref. 30857. 
Bagridae Mystus atrifasciatus Fowler, 1937 Fr native  Pba kahnyeng kang lai (Laotian)  15.00 cm SL male/unsexed  Occurs in the lower and middle Xe Bangfai, tributary of the Mekong (Ref. 27732). Museum: Mekong at Ban Hang Khone, just nelow Khone falls, CAS 96566 (Ref. 5515). Also Ref. 30857, 43281. 
Bagridae Mystus bocourti (Bleeker, 1864) Fr native  Pa kha gneng chong lang gnao (Laotian) scarce (very unlikely) 24.00 cm SL male/unsexed  Known from the Mekong River just below Lee Pee Waterfalls in southern Laos (Ref. 10418). Collected from Tha Bo and Sithan Tay (Ref. 4792). Also Ref. 30857, 36654, 37767, 43281. 
Bagridae Mystus cavasius (Hamilton, 1822) Fr misidentification  Pa ka gnen (Laotian)  40.00 cm SL male/unsexed  Known from the Mekong basin (Ref. 4792). Also Ref. 36654. 
Bagridae Mystus multiradiatus Roberts, 1992 Fr native  Pa kha gneng khang lai (Laotian)  12.80 cm SL male/unsexed  Found in the Mekong River. Occurs in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 30857. 
Bagridae Mystus mysticetus Roberts, 1992 Fr native  Pa kha gneng khang lai (Laotian), Pba kahnyeng kang lai (Laotian)  13.00 cm SL male/unsexed  Occurs in the middle Xe Bangfai, a tributary of the Mekong basin (Ref. 27732). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 30857, 43281. 
Bagridae Mystus nigriceps (Valenciennes, 1840) Fr native   30.00 cm TL male/unsexed  Known from the Mekong basin. 
Bagridae Mystus rhegma Fowler, 1935 Fr native  Pa ka gnen (Laotian)  12.00 cm SL male/unsexed  Known from the Mekong basin in Nam Ngum Dam site, Tha Ngon, Tha Bo, Sithan Tay and Hatsalao (Ref. 4792). Also Ref. 30857 (listed as Mystus cf. rhegma), 43281. 
Bagridae Mystus singaringan (Bleeker, 1846) Fr native  Pa kha gneng kho (Laotian), Pba kahnyeng koh (Laotian)  30.00 cm SL male/unsexed  Occurs in the Mekong. Found in the middle Xe Bangfai, a tributary of the Mekong basin (Ref. 27732) and Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Museum: Mekong below Khone falls, CAS 93466 (Ref. 5515). Also Ref. 10418, 30857, 43281. 
Bagridae Mystus vittatus (Bloch, 1794) Fr questionable  Pa ka gnen (Laotian)  21.00 cm SL male/unsexed  Reported from the Mekong basin (Ref. 4792). Also Ref. 36654. Occurrence needs confirmation as this species is known only from the Indian subcontinent (Ref. 26663). 
Nandidae Nandus nandus (Hamilton, 1822) Fr native  Pa ka (Laotian)  20.00 cm TL male/unsexed  Known from the Mekong basin. Also Ref. 4792. 
Nandidae Nandus nebulosus (Gray, 1835) Fr native   12.00 cm TL male/unsexed  Reported from the Mekong basin (Ref. 4792). 
Nandidae Nandus oxyrhynchus Ng, Vidthayanon & Ng, 1996 Fr native   6.90 cm SL male/unsexed  Widely distributed throughout the Mekong basin (Ref. 31543). 
Nemacheilidae Nemacheilus arenicolus Kottelat, 1998 Fr native   6.90 cm SL male/unsexed  Occurs in the middle and upper Nam Theun, a tributary of the Mekong (Ref. 27732). Also Ref. 43281.  No picture yet.
Nemacheilidae Nemacheilus longistriatus Kottelat, 1990 Fr native   12.50 cm SL male/unsexed  Occurs in the Mekong and the lower and middle Xe Bangfai (Ref. 27732). Listed as Nemacheilus cf. longistriatus in Ref. 30857. Also Ref. 43281. 
Nemacheilidae Nemacheilus pallidus Kottelat, 1990 Fr native   14.00 cm SL male/unsexed  Occurs in the lower and middle Xe Bangfai, a tributary of the Mekong basin (Ref. 27732). Also Ref. 30857, 39226, 43281. 
Nemacheilidae Nemacheilus platiceps Kottelat, 1990 Fr native   6.10 cm SL male/unsexed  Occurs in the Mekong and its tributary, the middle and upper Xe Bangfai (Ref. 27732). Also Ref. 30857, 43281. 
Odontobutidae Neodontobutis aurarmus (Vidthayanon, 1995) Fr native   5.50 cm SL male/unsexed  Occurs in the Mekong and the middle Nam Theun (Ref. 27732). Also Ref. 43281, 92840. 
Odontobutidae Neodontobutis tonkinensis (Mai, 1978) Fr native   4.90 cm SL male/unsexed  Occurs in the Nam Xam basin (Ref. 43281).  No picture yet.
Cyprinidae Neolissochilus blanci (Pellegrin & Fang, 1940) Fr native    Known from Ban Nam Khueng, 30 km northwest of Ban Houei Sai, about 6 km from Mekong (Ref. 94476).  No picture yet.
Cyprinidae Neolissochilus stracheyi (Day, 1871) Fr, Fi native   60.00 cm SL male/unsexed  Found in the Mekong and the upper Nam Theun basins (Ref. 27732). Also Ref. 4792, 12693, 30857. 
Notopteridae Notopterus notopterus (Pallas, 1769) Fr, Br, Fi, Thr native  Dtong (Laotian), Pa tong (Laotian), Pa tong na (Laotian), Pba dtawng noi (Laotian)  60.00 cm SL male/unsexed  Known from the Mekong basin (Ref. 43281). Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497), lower and middle Xe Bangfai rivers (Ref. 27732) and Tha Ngon and Tha Bo (Ref. 4792). Occurs above Pak Beng to Khoné Falls (Ref. 37772). Enters flooded forest (Ref. 9497). Common in the Mekong mainstreams as well as its tributaries, living in pools with submerged wood and shrubs (Ref. 37770). Reported to move into tributaries during the flood season to spawn (Ref. 37770). Museum: Mekong at Ban Hang Khone, just below Khone falls, CAS 96992 (Ref. 5515). Also Ref. 9497, 30857, 37767, 44002, 50526, 56905. 
Siluridae Ompok hypophthalmus (Bleeker, 1846) Fr native  Pa peek gai (Laotian)  30.00 cm SL male/unsexed  Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Undertakes upstream migration during the wet season in May-June through Hoo Som Yai at the Great Fault Line on the Mekong River, Champassack Province (Ref. 37771). Also Ref. 30857, 43281. 
Siluridae Ompok miostoma (Vaillant, 1902) Fr misidentification  Pa khoun (Laotian)  21.38 cm SL male/unsexed  Collected from Tha Ngon (Ref. 10421). 
Siluridae Ompok siluroides Lacepède, 1803 Fr native  Seum (Laotian), Pa seuam (Laotian)  21.44 cm SL male/unsexed  Occurs in the Mekong basin (Ref. 9497). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Collected from Tha Ngon, Tha Bo, Sithan Tay and Hatsalao in the Mekong basin (Ref. 4792). Undertakes upstream migration during the wet season in May-June through Hoo Som Yai at the Great Fault Line on the Mekong River, Champassack Province (Ref. 37771). Also Ref. 30857, 43281. 
Siluridae Ompok urbaini (Fang & Chaux, 1949) Fr native   18.10 cm SL male/unsexed  Known from Mekong River at Ban Hang Khone, just downstream from Khone Falls (Ref. 52514). 
Cyprinidae Onychostoma elongatum (Pellegrin & Chevey, 1934) Fr native   11.50 cm SL male/unsexed  Occurs in the Nam Ma basin (Ref. 43281). 
Cyprinidae Onychostoma fangi Kottelat, 2000 Fr questionable   29.50 cm TL male/unsexed  Listed as Onychostoma cf. elongatum in Ref. 30857; occurrence needs verification. Also Ref. 37767. 
Cyprinidae Onychostoma fusiforme Kottelat, 1998 Fr native   23.00 cm SL male/unsexed  Known from the Mekong basin in the upper, middle and lower Nam Theun basins (Ref. 27732). Also Ref. 43281.  No picture yet.
Cyprinidae Onychostoma gerlachi (Peters, 1881) Fr native   31.64 cm SL male/unsexed  Known from the Mekong basin in northern Laos and Nam Ma basin. 
Cyprinidae Onychostoma lepturus (Boulenger, 1900) Fr native   23.82 cm SL male/unsexed  Occurs in northerneastern Viet Nam (Ref. 43281).  No picture yet.
Cyprinidae Onychostoma meridionale Kottelat, 1998 Fr native   14.00 cm SL male/unsexed  Found in the Mekong basin in central and southern Laos (Ref. 43281). Recorded from the upper Xe Bangfai, a tributary of the Mekong (Ref. 27732).  No picture yet.
Xenocyprididae Opsariichthys bidens Günther, 1873 Fr native   26.10 cm TL male/unsexed  Found in northeastern Laos. 
Danionidae Opsarius barna (Hamilton, 1822) Fr native   15.00 cm TL male/unsexed  Known from the Mekong basin. 
Danionidae Opsarius koratensis (Smith, 1931) Fr native  Pa sieu (Laotian)  16.00 cm TL male/unsexed  Occurs in the Mekong and its tributaries (lower and middle Xe Bangfai basin). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 4792, 30857, 36654, 37788, 43281. 
Danionidae Opsarius pulchellus (Smith, 1931) Fr native  Pa lai khouang (Laotian)  11.00 cm SL male/unsexed  Occurs in the Mekong basin and its tributaries, the middle Xe Bangfai and the lower and middle Nam Theun (Ref. 27732). Found also in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767) and in Luang Prabang, Sithan Tay and Bang Lieng in the Mekong basin (Ref. 4792). Recorded from the Nam Ma basin (Ref. 43281). Also Ref. 30857, 37788. 
Cyprinidae Oreichthys parvus Smith, 1933 Fr native   3.00 cm SL male/unsexed  Occurs in the middle Xe Bangfai, a tributary of the Mekong (Ref. 27732). Also Ref. 30857, 43281. 
Cichlidae Oreochromis mossambicus (Peters, 1852) Fr introduced   39.00 cm SL male/unsexed  Highly preferred food fish (Ref. 58867). 
Cichlidae Oreochromis niloticus (Linnaeus, 1758) Fr, Br, Fi, Aq introduced  Nin (Laotian)  60.00 cm SL male/unsexed  Occurs in the Mekong along the Thai-Lao border (Ref. 12693). Introduced for aquaculture in ponds but also released into reservoirs and rivers (Ref. 43281). Highly preferred food fish (Ref. 58867). Also Ref. 8984, 12228, 30857, 56905. 
Sisoridae Oreoglanis delacouri (Pellegrin, 1936) Fr native   12.30 cm SL male/unsexed   and Nam Ngiap basin (Ref. 43281). 
Sisoridae Oreoglanis frenata Ng & Rainboth, 2001 Fr native   9.25 cm SL male/unsexed  Type locality, Nam Ka basin, Houay Kheua at Hwy 7 bridge, 19°38'N, 103°28'E, Xieng Khouang Prov. (Ref. 44353).  No picture yet.
Sisoridae Oreoglanis hypsiura Ng & Kottelat, 1999 Fr native   13.80 cm SL male/unsexed  Known from the Mekong basin. Found in Nam Theun basin, part of the Mekong River drainage (Ref. 37793); including upper Nam Theun, ca 1 km upstream of confluence with Houay Nuok Lan, Khammouan Prov. (Ref. 44353); and, and Nam Kading basin (Ref. 43281).  No picture yet.
Sisoridae Oreoglanis lepturus Ng & Rainboth, 2001 Fr native   9.08 cm SL male/unsexed  Type locality, Nam Phao ca. 2 km from Vietnam border, 18°23'N, 105°19'E, Bolikamsai Prov. (Ref. 44353).  No picture yet.
Sisoridae Oreoglanis macronemus Ng, 2004 Fr native   6.47 cm SL male/unsexed  Known from Xieng Khouang region, most likely from either the Nam Ngiap or the Nam Sen drainage (Ref. 55772).  No picture yet.
Sisoridae Oreoglanis setigera Ng & Rainboth, 2001 Fr native   6.91 cm SL male/unsexed  Known from the Nam Oun River drainage (part of the Mekong R. drainage) in northwestern Laos. Type locality, Nam Ma Oun, Louang Namtha Prov., holotype of O. setiger, 6.91 cm SL) (Ref. 44353).  No picture yet.
Adrianichthyidae Oryzias latipes (Temminck & Schlegel, 1846) Fr native   4.00 cm SL male/unsexed  Occurs in the Mekong and the middle Nam Theun (Ref. 27732). 
Adrianichthyidae Oryzias mekongensis Uwa & Magtoon, 1986 Fr native   3.00 cm TL male/unsexed  Occurs in the Mekong basin (Ref. 43281). Known from Nong Seng, a swamp 7 km southeast of Ban Talang, Nakai plateau, Nan Theum watershed (Ref. 27658). Also Ref. 30857. 
Adrianichthyidae Oryzias minutillus Smith, 1945 Fr native   2.00 cm TL male/unsexed  Expected to occur in Laos (Ref. 43281). 
Adrianichthyidae Oryzias pectoralis Roberts, 1998 Fr native   2.23 cm SL male/unsexed  Known from rice paddies on the Nakai plateau in Nam Theun watershed (Mekong basin) of central Laos (Ref. 27658), Xe Bang Hiang (Mekong basin) and Nam Ma basin (Ref. 43281). 
Adrianichthyidae Oryzias sinensis Chen, Uwa & Chu, 1989 Fr native   3.10 cm SL male/unsexed  Occurs in the Mekong basin (Ref. 43281). 
Adrianichthyidae Oryzias songkhramensis Magtoon, 2010 Fr native   1.90 cm SL male/unsexed    No picture yet.
Osphronemidae Osphronemus exodon Roberts, 1994 Fr, Fi native  Men (Laotian), Pa haet (Laotian), Pa men (Laotian), Pba men (Laotian)  60.00 cm SL male/unsexed  Occurs in the Mekong basin. Found in the middle Xe Bangfai, a Mekong tributary (Ref. 27732). Recorded from just above the Lee Pee or Khone waterfalls (Ref. 31465). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767), Ngam Ngum Reservoir and Vientiane (Ref. 12369). In Thakhek, it occurs under shrubs in pools of the main Mekong River near the mouths of tributaries (Ref. 37770). Museum: Mekong river at Takam on Don Som, just opposite Kinnak and 12 km above Lee Pee waterfalls, CAS 81553 (Ref. 5515). Also Ref. 12693, 30857, 43281, 50526. 
Osphronemidae Osphronemus goramy Lacepède, 1801 Fr, Br, Fi native  Pa men (Laotian), Pa meng (Laotian)  70.00 cm SL male/unsexed  Known from the Mekong basin around Pak Beng to the Khone Falls (Ref. 37772). Found in Ban Hang Khone at Don Khone, about 3 km below the fall line of the great waterfalls of the Mekong River at Lee Pee (Ref. 9497). Enters flooded forest (Ref. 9497). Specimens of this species previously reported from Ban Hang Khone (Ref. 9497) have been reidentified as O. exodon (Ref. 12369). This fish probably does not occur naturally in the Mekong basin (Ref. 12369). Also Ref. 4792, 4796, 31465, 56905. 
Cyprinidae Osteochilus enneaporos (Bleeker, 1852) Fr native   23.00 cm SL male/unsexed   
Cyprinidae Osteochilus lini Fowler, 1935 Fr native  Pa soi (Laotian)  15.00 cm SL male/unsexed  Known from the Mekong in the Xe Bangfai basin (Ref. 27732). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 4792, 30857, 43281. 
Cyprinidae Osteochilus melanopleura (Bleeker, 1852) Fr, Fi native  Nok khao (Laotian), Pa nok khao (Laotian)  60.00 cm SL male/unsexed  Known from the Mekong in the middle Xe Bangfai basin (Ref. 27732). A migratory species occurring above Pak Beng to the Khone Falls (Ref. 37772). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Museum: Mekong river at Ban Hang Khone, just below Khone falls, CAS 96548 (Ref. 5515). Also Ref. 4792, 2091, 30857, 56905. 
Cyprinidae Osteochilus microcephalus (Valenciennes, 1842) Fr native  Pa khang lai gnai (Laotian), Pba kang lai (Laotian)  24.00 cm SL male/unsexed  Occurs in the Mekong River (Ref. 43281). Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Undertakes upstream migration during the wet season in June-July through Hoo Som Yai at the Great Fault Line on the Mekong River, Champassack Province (Ref. 37771). Also Ref. 30857, 36654, 37767. 
Cyprinidae Osteochilus salsburyi Nichols & Pope, 1927 Fr native   20.10 cm TL male/unsexed  Known from the Nam Xam and Nam Ma basins (Ref. 43281). 
Cyprinidae Osteochilus striatus Kottelat, 1998 Fr native   8.20 cm SL male/unsexed  Occurs in the middle Xe Bangfai of the Mekong basin (Ref. 27732). Also Ref. 43281.  No picture yet.
Cyprinidae Osteochilus vittatus (Valenciennes, 1842) Fr, Fi native  Pa khi ka pheuay (Laotian), I Thai (Laotian), Pa khao mong (Laotian), Pba kee ga peu (Laotian)  32.00 cm SL male/unsexed  Occurs in the Mekong in the middle Xe Bangfai basin (Ref. 27732). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Undertakes upstream migration during the wet season in June-July through Hoo Som Yai at the Great Fault Line on the Mekong River, Champassack Province (Ref. 37771). Museum: Mekong river, CAS 93259 (Ban Hang Khone, just below Khone falls); CAS 93269 (below Khone falls) (Ref. 5515). Also Ref. 4792, 2686, 30857, 37769, 43281. 
Cyprinidae Osteochilus waandersii (Bleeker, 1853) Fr, Fi native  Pa khang lai gnai (Laotian), Pba kang lai (Laotian)  27.60 cm TL male/unsexed  Occurs in the middle Xe Bangfai of the Mekong basin (Ref. 27732). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 4792, 7050, 30857. 
Butidae Oxyeleotris marmorata (Bleeker, 1852) Fr, Br, Fi native  Pa bou (Laotian), Pa boo (Laotian), Pa bout (Laotian)  65.00 cm SL male/unsexed  Known from the Mekon basin. Occurs in the Khone Falls (Ref. 37772). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Enters flooded forest on Don Khone, just below the great waterfalls (Ref. 9497). Also Ref. 7050, 30857, 56905. 
Xenocyprididae Oxygaster anomalura Van Hasselt, 1823 Fr native   20.00 cm SL male/unsexed  Occurs in the Mekong River. 
Xenocyprididae Oxygaster pointoni (Fowler, 1934) Fr native  Pa thep (Laotian)  15.50 cm SL male/unsexed  Occurs in the middle Xe Bangfai River, a tributary of Mekong basin (Ref. 27732). Collected from Nam Ngum dam site, Tha Ngon, Tha Bo and Sithan Tay in the Mekong basin (Ref. 4792). Also Ref. 30857, 43281. 
Pangasiidae Pangasianodon gigas Chevey, 1931 Fr, Fi, Pr, Thr native  Pa beuk (Laotian), Pa boeuk (Laotian) scarce (very unlikely) 300 cm TL male/unsexed ;235 cm SL female  Very rare but prized fish in the Mekong. Catch, sale and transportation are forbidden under the Fiat-Law on Fishery Management and Administration No. 33 KRO.CHOR of 19 March 1987, as Pangasianodon gigas (Ref. 12217). Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). In Bokeo Province, this species migrates upstream during April-May. This movement is triggered by the first rain and increased water turbidity. Reported to spend the dry season in deep pools in the Mekong mainstream in Xayaboury Province (Ref. 37770). Museum: Mekong river, Laos BMNH 1977.4.21.1-2 (Ref. 31982). Also Ref. 3881, 4792, 30857, 36654, 37772, 43281, 56905. 
Pangasiidae Pangasianodon hypophthalmus (Sauvage, 1878) Fr, Fi native  Pa souay kheo (Laotian), Pa sooai (Laotian), Pa sooai khaeo (Laotian)  130 cm SL male/unsexed  Known from the Mekong River (Ref. 43281). A migratory species that is found around Pak Beng to the Khone Falls (Ref. 37772). Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Undertakes upstream migration during the wet season in May-June through Hoo Som Yai at the Great Fault Line on the Mekong River, Champassack Province (Ref. 37771). Considered one of the important pangasid species in the Khone Falls "lee" (wing) trap fsihery during May to July each year (Ref. 37770). Also Ref. 4792, 30857, 37767, 56905. 
Pangasiidae Pangasius bocourti Sauvage, 1880 Fr, Fi native  Pa yang (Laotian), Pa hua muam (Laotian), Pba hua muam (Laotian)  120 cm SL male/unsexed  Found in the Mekong River (Ref. 30857). Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Undertakes upstream migration in June-July at Champassack Province, Southern Laos (Ref. 37771). Enters the flooded forest during high water (July-October) and feeds mainly on fruits (Ref. 9497). Museum: Mekong at Ban Hang Khone, just below Khone falls, CAS 94876 (Ref. 5515). Also Ref. 37767, 41485, 43281, 56905. 
Pangasiidae Pangasius conchophilus Roberts & Vidthayanon, 1991 Fr, Fi native  Por (Laotian), Pa gae (Laotian), Pa ke-pa pho (Laotian), Pa paw (Laotian), Pba gae (Laotian)  120 cm SL male/unsexed  Found in the Mekong River (Ref. 43281). Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Enters flooded forest (Ref. 9497). The most important pangasiid in the overall fish catch at Ban Hang Khone during June-July 1993 (Ref. 9497). During the period of high water (July-October) it enters the flooded forest and feeds heavily on fruits (Ref. 9497). Migrates upstream from March to August from the Khong Island, just upstream Khone Falls in Laos to Chiang Saen in Thailand (Ref. 37770). Also undertakes reproductive and trophic upstream migrations through Hoo Som Yai at the Great Fault Line on the Mekong River, Champassack Province (Ref. 37771). Museum: Mekong at Ban Hang Khone, just below Khone falls, CAS 94870 (Ref. 5515). Also Ref. 7432, 30857, 37767, 37769, 44002, 56905. 
Pangasiidae Pangasius djambal Bleeker, 1846 Fr, Fi native   90.00 cm TL male/unsexed  Known from the Mekong basin. Migrates upstream from May, when the water level rises, until August (Ref. 37770). Undertakes downstream migration in Savannakhet during October-November (Ref. 37770). Small juveniles (2-4 cm) have been encountered at Savannakhet from May to November (Ref. 37770). 
Pangasiidae Pangasius elongatus Pouyaud, Gustiano & Teugels, 2002 Fr native  Pa gnone hang hian (Laotian), Pa nyawn hang hian (Laotian)  28.20 cm SL male/unsexed  Known from the Mekong basin downriver of Khone Falls (Ref. 43281). Has not been found in the Mekong above the waterfalls (Ref. 9497). Occurs in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). At Khanthaboury, Savannakhet, it migrates upstream in schools together with other species. However, the downstream movements are more sporadic and not done with other species (Ref. 37770). Also Ref. 30857, 37767.  No picture yet.
Pangasiidae Pangasius krempfi Fang & Chaux, 1949 Fr, Br, Fi, Thr native  Pa souay hang leuang (Laotian), Pa sooai (Laotian), Pa sooai hang luang (Laotian), Pba sooay hang leuang (Laotian), Pba sooay mak mai (Laotian)  120 cm SL male/unsexed  Known from Mekong basin (Ref. 30857). Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). One of the most important migratory pangasiid species at Ban Hang Khone. Reproduction presumably takes place in or along the Mekong delta. Migratory fish generally have empty stomach. Enters the flooded forest and feeds on mak deua (Ref. 9497). Upstream the Khone Falls, it migrates upstream from May to September, dominated by fish in spawning condition (Ref. 37770). Above the Khone Falls, dowstream migration takes place in October (Ref. 37770). These migrations are triggered by the increase of the water levels above the Khone Falls (Ref. 37770). Also Ref. 37767, 43281. 
Pangasiidae Pangasius larnaudii Bocourt, 1866 Fr, Fi native  Beung (Laotian), Pa hou mat (Laotian), Pa pboong (Laotian), Pa peung (Laotian), Pba beung (Laotian)  130 cm SL male/unsexed  Occurs in the Mekong tributary, the lower Xe Bangfai basin (Ref. 27732). Found in the Khone Falls (Ref. 37772). Collected from Tha Ngon in the Mekong basin (Ref. 4792) and from Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Enters flooded forest in Ban Hang Khone, Don Khone, just below the great waterfalls at Lee Pee (Ref. 9497). Undertakes upstream migration during the wet season in May-July through Hoo Som Yai at the Great Fault Line on the Mekong River, Champassack Province (Ref. 37771). Also Ref. 9497, 30857, 37771, 43281, 44002, 56905. 
Pangasiidae Pangasius macronema Bleeker, 1850 Fr, Fi native  Nyawn (Laotian), Pa nyawn (Laotian), Pba nyawn (Laotian)  30.00 cm SL male/unsexed  Known from the Mekong basin (Ref. 43281). Occurs in the Khone Falls in the Mekong basin (Ref. 37772) and Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Collected from Hatdokkeo, Tha Bo, Sai Fong, Sithan Tay, Hatsalao and Pathoun Phon of the Mekong basin (Ref. 4792). Among the most important species in the fisheries based on migrations in January-February and May-June (Ref. 9497). A strongly migratory fish species in the Khone area that does not go to Tam Ee Daeng, may be because it migrates upstream at a time when waters are low (April-early May) than when other species migrate. It goes only as far upstream as Boong Pba Jook (across from Hang Khone) before turning back and going up the channel to Hoo Sahong (Ref. 12369). Villagers catch them in the deep pools near the mouth of Hoo Sahong between Don Khone and Don Sadam (Ref. 12369). Fishers in Xayabury Province reported that it migrates downstream in October-November (Ref. 37770). Undertakes upstream migration during the wet season in May-June through Hoo Som Yai at the Great Fault Line on the Mekong River, Champassack Province (Ref. 37771). Museum: Mekong at Ban Hang Khone, just below Khone falls, CAS 94882 (Ref. 5515). Listed in Ref. 30857 as Pangasius cf. siamensis. P. macronema is an important fishery in the villages of Hang Sadam, Don Sahong, and Houa Sadam (Ref. 44002). Also Ref. 56905. 
Pangasiidae Pangasius nasutus (Bleeker, 1863) Fr native  Pa ling (Laotian)  90.00 cm TL male/unsexed  Recorded from the Mekong basin at Tha Bo and Hatsalao. 
Pangasiidae Pangasius pangasius (Hamilton, 1822) Fr questionable  Pa souei (Laotian)  300 cm SL male/unsexed  Status uncertain and needs confirmation. This species was probably introduced in the Mekong basin. Collected from Hatdokkeo, Tha Bo, Sai Fong and Sithan Tay in the Mekong basin. 
Pangasiidae Pangasius sanitwongsei Smith, 1931 Fr, Fi, Thr native  Pba leum (Laotian), Pa leum (Laotian)  300 cm SL male/unsexed  Migratory; upstream Mekong. Its numbers have declined in the Khone Falls (Ref. 37772). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also collected from Tha Ngon in the Mekong basin (Ref. 4792). There is a recent decline in abundance; caught with "bet ken" (large hooks) set in isolated "gohk goom" (Crateva nurvala, Capparidaceae trees) (Ref. 9497). In Southern Laos, this fish used to be relatively abundant; big fish are now rare. Many young fish of about 40 g were observed in November-December 1993 as well as in other months. Large fish with eggs were found in June-July and may spawn in Boong Pba Leum, where large fish have been seen surfacing in June and July (Ref. 12369). Also previously caught with hooks in Hoo Sadam, but they are now seldom seen or caught there (Ref. 12369). Also Ref. 2686, 30857, 43281, 56905. 
Cobitidae Pangio anguillaris (Vaillant, 1902) Fr native   12.00 cm SL male/unsexed  Known from the Mekong basin in the lower and middle Xe Bangfai (Ref. 27732). Collected from Hatsalao (Ref. 4792). Also Ref. 30857, 13770, 36654, 43281. 
Cobitidae Pangio fusca (Blyth, 1860) Fr native   8.00 cm SL male/unsexed  Occurs in the middle Nam Theun, a tributary of the Mekong (Ref. 27732). Also Ref. 30857, 43281. 
Cobitidae Pangio longimanus Britz & Kottelat, 2010 Fr native      No picture yet.
Cobitidae Pangio muraeniformis (de Beaufort, 1933) Fr questionable   3.60 cm SL male/unsexed  Outside distributional range, occurrence needs verification.  No picture yet.
Cobitidae Pangio myersi (Harry, 1949) Fr native   10.00 cm SL male/unsexed  Known from the Mekong basin downriver of Khone Falls (Ref. 43281). 
Cobitidae Pangio oblonga (Valenciennes, 1846) Fr native   8.00 cm TL male/unsexed  Occurs in the Mekong basin (Ref. 43281). Also Ref. 7050, 50526. 
Tetraodontidae Pao abei (Roberts, 1998) Fr native  scarce (very unlikely) 10.30 cm SL male/unsexed  Found in Mekong basin at Xe bang Fai watershed and at Hang Khone, just below Khone waterfalls (Ref. 27661). Also Ref. 94476. 
Tetraodontidae Pao baileyi (Sontirat, 1985) Fr native  Pa pao thong (Laotian), Pba pbao (Laotian)  12.00 cm SL male/unsexed  Occurs in the Mekong River (Ref. 27661). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Museum: Mekong river at Ban Hang Khone, just below Khone falls, CAS 93055 (Ref. 5515). Also Ref. 30857, 43281, 50526. 
Tetraodontidae Pao brevirostris (Benl, 1957) Fr native   9.46 cm SL male/unsexed ;7.72 cm SL female  Known from the middle Mekong, upstream of Khone Falls (Ref. 81211).  No picture yet.
Tetraodontidae Pao cambodgiensis (Chabanaud, 1923) Fr native   15.30 cm SL male/unsexed  Occurs in the Mekong basin (Ref. 43281); at Hang Khone, below Khone Falls (Ref. 27661). Also Ref. 30857, 94476. 
Tetraodontidae Pao cochinchinensis (Steindachner, 1866) Fr native   11.28 cm SL male/unsexed  Occurs in the Mekong basin (Ref. 43281). 
Tetraodontidae Pao leiurus (Bleeker, 1850) Fr native  Pa pao (Laotian), Pba pbao (Laotian)  16.00 cm male/unsexed  Known from Mekong (Ref. 27661). Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Also Ref. 4792, 37767, 50526. 
Tetraodontidae Pao palembangensis (Bleeker, 1851) Fr native   19.40 cm SL male/unsexed  Occurs in the Mekong (Ref. 2091). 
Tetraodontidae Pao suvattii (Sontirat & Soonthornsatit, 1985) Fr native   11.50 cm SL male/unsexed  Occurs in the Mekong and the lower Xe Bangfai (Ref. 27732). Also Ref. 27661, 43281. 
Tetraodontidae Pao turgidus (Kottelat, 2000) Fr native   18.50 cm SL male/unsexed  Occurs in the Mekong basin (Ref. 36949, 43281). 
Gobiidae Papuligobius ocellatus (Fowler, 1937) Fr native   12.00 cm SL male/unsexed  Occurs in the Mekong, the lower, middle and upper Xe Bangfai, and the lower and middle Nam Theun (Ref. 27732). Also Ref. 4792, 30857, 43281. 
Gobiidae Papuligobius uniporus Chen & Kottelat, 2003 Fr native   6.51 cm SL male/unsexed  Occurs only in the Nam Mat basin (Ref. 43281, 52877). The Nam Mat is a tributary of the Ca River which enters the Gulf of Tonkin in Vinh, Vietnam (Ref. 52877).  No picture yet.
Xenocyprididae Parachela maculicauda (Smith, 1934) Fr native   6.00 cm TL male/unsexed  Occurs in the Mekong River (Ref. 43281). Recorded near Vientiane (Ref. 12693). Also Ref. 30857. 
Xenocyprididae Parachela oxygastroides (Bleeker, 1852) Fr native  Pa thep (Laotian)  20.00 cm SL male/unsexed  Occurs in the Mekong River (Ref. 30857). Collected from Tha Ngon and Tha Bo in the Mekong basin (Ref. 4792). Also Ref. 2686, 36654. 
Xenocyprididae Parachela siamensis (Günther, 1868) Fr native  Pa tep houa beut (Laotian)  19.00 cm TL male/unsexed  Occurs in the Mekong basin. Found in the lower Xe Bangfai River (Ref. 27732) and in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 30857, 43281. 
Xenocyprididae Parachela williaminae Fowler, 1934 Fr native   12.00 cm SL male/unsexed  Known from the Mekong River. Also Ref. 4792, 30857. 
Xenocyprididae Paralaubuca barroni (Fowler, 1934) Fr native   15.00 cm SL male/unsexed  Occurs in Mekong and its tributary, the lower Xe Bangfai basin (Ref. 27732). Also Ref. 4792, 43281. 
Xenocyprididae Paralaubuca harmandi Sauvage, 1883 Fr native   21.90 cm SL male/unsexed  Known from the Mekong River. Also Ref. 36654. 
Xenocyprididae Paralaubuca riveroi (Fowler, 1935) Fr native  Paep (Laotian)  18.00 cm SL male/unsexed  Reported from the Mekong basin at Tha Ngon (Ref. 4792). 
Xenocyprididae Paralaubuca stigmabrachium (Fowler, 1934) Fr native  Pa thep (Laotian)   Known from the Mekong basin at Pak Soung, Isl. Don Tio, Nam Ngum dam site, Tha Ngon, Isl. Don Tiane, Tha Bo, Sithan Tay, Sai Fong, Hatsalao, Pathoum Phon and Khinak (Ref. 4792).  No picture yet.
Xenocyprididae Paralaubuca typus Bleeker, 1864 Fr, Fi native  Dtaep (Laotian), Pa tep (Laotian), Pba dtep (Laotian)  18.00 cm SL male/unsexed  Known from the Mekong basin. Found in the lower and middle Xe Bangfai River (Ref. 27732) and in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Collected from Tha Ngon and Hatsalao in the Mekong basin (Ref. 4792). One of the most important fishes in the specialized "tone" trap fishery at Ban Hang Khone form January to March (Ref. 37770). This fishery mainly targets small highly migratory cyprinids (Ref. 37770). Reported to migrate upstream during the dry season in December/March in Southern Laos (Ref. 37769). Also Ref. 30857, 36654. 
Ambassidae Parambassis apogonoides (Bleeker, 1851) Fr native  Pa kahpkawng (Laotian)  10.00 cm SL male/unsexed  Known from the lower Mekong basin below Lee Pee Waterfalls (Ref. 10429). Museum: Mekong below Khone falls, CAS 93275 (Ref. 5515). Also Ref. 9497, 30857. 
Ambassidae Parambassis siamensis (Fowler, 1937) Fr native  Pa kahpkawng (Laotian), Pa khap khong (Laotian), Pba kahp kawng (Laotian)  7.50 cm SL male/unsexed  Occurs in the Mekong basin. Found in the lower and middle Xe Bangfai (Ref. 27732) and Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Collected from Luang Prabang, Tha Ngon, Tha Bo, Sai Fong, Sithan Tay, Hatsalao (Ref. 4792). Museum: Mekong below Khone falls, CAS 97001 (Ref. 5515). Also Ref. 30857, 36654, 50526. 
Ambassidae Parambassis wolffii (Bleeker, 1850) Fr native  Pa khap khong (Laotian), Pa kahpkawng (Laotian)  20.00 cm SL male/unsexed  Known from the Mekong basin (Ref. 43281). Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Museum: Mekong river at Ban Hang Khone, just below Khone falls, CAS 94295, 96631 (Ref. 5515). Also Ref. 30857, 37767. 
Sisoridae Pareuchiloglanis nebulifera Ng & Kottelat, 2000 Fr native   9.60 cm SL male/unsexed  Known from the Nam Xam and a tributary of the Nam Ma basins (Ref. 43281). Also Ref. 37037, 44416.  No picture yet.
Cyprinidae Pethia stoliczkana (Day, 1871) Fr native   5.00 cm SL male/unsexed  Known from the upper Mekong basin (Ref. 43281). 
Cyprinidae Pethia ticto (Hamilton, 1822) Fr native   12.52 cm TL male/unsexed  Known from the upper Mekong basin. 
Siluridae Phalacronotus apogon (Bleeker, 1851) Fr, Fi native  Pba nang (Laotian), Pa nang (Laotian), Pa sa ngoua (Laotian)  130 cm SL male/unsexed  Occurs in the Mekong basin. Recorded from the lower Xe Bangfai (Ref. 27732), Khone Falls (Ref. 37772) and Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 4792, 30857, 43281, 56905. 
Siluridae Phalacronotus bleekeri (Günther, 1864) Fr, Fi, Thr native  Nang (Laotian), Pa kayt (Laotian), Pa nang ngeun (Laotian), Pa souam (Laotian)  60.00 cm SL male/unsexed  Known from the Mekong River (Ref. 30857). Collected from Tha Ngon, Tha Bo, Sithan Tay and Hatsalao of the Mekong basin (Ref. 4792). Occurs in the Khone Falls (Ref. 37772). Also found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 36654, 43281, 56905. 
Siluridae Phalacronotus micronemus (Bleeker, 1846) Fr native  Pa nang khao (Laotian)  50.00 cm SL male/unsexed  Known from the Mekong River. Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 44002. 
Cyprinidae Placocheilus caudofasciatus (Pellegrin & Chevey, 1936) Fr native   10.90 cm SL male/unsexed  Occurs in the Nam Ma basin (Ref. 43281).  No picture yet.
Plotosidae Plotosus canius Hamilton, 1822 Fr native  Pa duk taleh (Laotian), Pa lai fai fa (Laotian) scarce (very unlikely) 111 cm TL male/unsexed  A single individual 111 cm TL) was caught in a fyke net set overnight (5-6 August 2016 while the river was in flood and was highly turbid, as is usual for the monsoon season) in about 1 m of water near the eastern shore of Phapheng Channel, the most easterly of the Khone Falls channels, It was previously included in list of species occurring in the area (Ref. 9497) but has not been observed in Ban Hang Khone until 2016. Fishermen fishing at Khone Falls reported that some of them may have caught one or two specimens of P. canius, which were however much smaller in size (~50 cm TL) than the specimen recorded herein. Its undifferentiated gut was approximately half-full of fragments of crabs and molluscs, with some detritus and sediment, with the food items dispersed along the length of its gut (Ref. 127983). Also Ref. 3478. 
Polynemidae Polynemus aquilonaris Motomura, 2003 Fr native   15.80 cm SL male/unsexed  Occurs in southernmost Laos, in the Mekong River system below the Khone waterfalls (Ref. 49954, 57343). 
Polynemidae Polynemus dubius Bleeker, 1853 Fr questionable  Pa chin (Laotian)  20.00 cm SL male/unsexed  Known from the Mekong basin downriver of Khone Falls (Ref. 43281). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 30857. Outside distributional range. 
Cyprinidae Poropuntius alloiopleurus (Vaillant, 1893) Fr native   40.00 cm SL male/unsexed  Known from the Nam Xam and Nam Ma basins.  No picture yet.
Cyprinidae Poropuntius angustus Kottelat, 2000 Fr native   12.00 cm SL male/unsexed  Presently known only from northern Laos, from Nam Ou, Nam Tha and Nam Youan basins (Ref. 36949). Also Ref. 43281.  No picture yet.
Cyprinidae Poropuntius bolovenensis Roberts, 1998 Fr, Thr native   20.00 cm SL male/unsexed  Occurs in the streams on the summit of the Bolovens Plateau in the Sekong watershed of the lower Mekong basin. Known from two of the largest streams on the plateau, the upper Xe Nam Noi and the upper Xe Pian (absent from lower reaches). These two river systems are isolated from their lower reaches by high waterfalls (Ref. 35912). Also Ref. 36949., 43281, 56905. 
Cyprinidae Poropuntius carinatus (Wu & Lin, 1977) Fr native   23.00 cm SL male/unsexed  Occurs in the Mekong basin (Ref. 43281).  No picture yet.
Cyprinidae Poropuntius consternans Kottelat, 2000 Fr native   12.40 cm SL male/unsexed  Known from the Xe Kong tributaries on Bolaven Plateau (Ref. 43281). Occurs in Xe Nam Noi of the Mekong basin (Ref. 36949).  No picture yet.
Cyprinidae Poropuntius deauratus (Valenciennes, 1842) Fr questionable  Jat (Laotian), Pa chat hang leuang (Laotian), Pba jaht (Laotian)  16.95 cm TL male/unsexed  Not in Kottelat (2001, Ref. 43281) and outside the range given by Ref. 36949; probably a misidentification. Reported from the Mekong basin (Ref. 30857) and found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Museum: Mekong river at Ban Hang Khone, CAS 94481; just below Khone falls, CAS 94480 (Ref. 5515). Also Ref. 4792, 37769, 50526. 
Cyprinidae Poropuntius huguenini (Bleeker, 1853) Fr questionable   46.00 cm TL male/unsexed  Occurs in the Mekong basin. Collected from Tha Bo, Sithan Tay (Ref. 4792).  No picture yet.
Cyprinidae Poropuntius krempfi (Pellegrin & Chevey, 1934) Fr native   13.00 cm SL male/unsexed  Occurs in Nam Ma basin (Ref 43281).  No picture yet.
Cyprinidae Poropuntius laoensis (Günther, 1868) Fr, Sp native  Pla Tchat (Laotian)  32.00 cm TL male/unsexed  Occurs in the Xe Bangfai of the Mekong basin (Ref. 27732). Listed as Poropuntius cf. laoensis in Ref. 30857. Also Ref. 12693, 35912, 36949, 43281, 83663. 
Cyprinidae Poropuntius lobocheiloides Kottelat, 2000 Fr native   13.80 cm SL male/unsexed  Occurs in the Xe Nam Noi 300 m dowstream from main dam site for Xe Nam Noi-Xe Pian hydropower scheme, Bolovens Plateau, Sekong watershed in the Mekong basin (Ref. 36949). Also Ref. 43281.  No picture yet.
Cyprinidae Poropuntius normani Smith, 1931 Fr native   13.00 cm SL male/unsexed  Occurs in the Mekong basin (Ref. 43281). 
Cyprinidae Poropuntius solitus Kottelat, 2000 Fr native   9.20 cm SL male/unsexed  Occurs in Xe Nam Noy basin of the Mekong. Also Ref. 43281.  No picture yet.
Pristidae Pristis microdon Latham, 1794 Fr, Br native  scarce (very unlikely) 700 cm TL male/unsexed  Found in the Mekong basin downstream of Khone falls (Ref. 43281). Also Ref. 12693, 30857. 
Pristolepididae Pristolepis fasciata (Bleeker, 1851) Fr, Fi native  Pa ka (Laotian), Pa gah (Laotian)  31.00 cm TL male/unsexed  Occurs in the Mekong basin. Found in the lower and middle Xe Bangfai (Ref. 27732), Mekong mainstream at Hat Village, Muang Khong District (Ref. 37769) and Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Enters flooded forest on Don Khone, just below the great waterfalls (Ref. 9497). Also Ref. 4792, 9497, 30857, 36654, 43281, 50526. 
Cyprinidae Probarbus jullieni Sauvage, 1880 Fr, Br, Fi, Pr native  Eun (Laotian), Pa eun (Laotian), Pa eun ta deng (Laotian), Pa uhn (Laotian), Pba eun (Laotian), Pba eun dta deng (Laotian) scarce (very unlikely) 150 cm SL male/unsexed  Found mainly in the mainstream of large rivers. In the Mekong it is nearly restricted to the Mekong mainstream. Found below Mun-Chin River to the Khone Falls (Ref. 37772). Exclusive or nearly exclusive fishing for the species occurs only during the upstream reproductive migrations and actual spawning periods in the area near the Lee Pee Waterfalls in southern Laos. Farther upstream the fishery occurs at progressively later times. This important fisheries species is under serious longterm decline and this decline evidently is basinwide and the most obvious (but not necessarily only) reason is overfishing with gillnets during the reproductive migrations and spawning periods (Ref. 10431). Found mainly in deep slow reaches of the Mekong basin at Hee Village, Muang Mouan; undertakes upstream migration in November-January/February at Hee Village, Muang Mouan (Ref. 37769). Highly esteemed expensive food fish, locally consumed. Migrates upstream in October-December; according to Ban Hang Khone fishermen stock has declined 90% of 1970 level (Ref. 9497). Also undertakes downstream migration during the wet season in June-July through Hoo Som Yai at the Great Fault Line on the Mekong River, Champassack Province (Ref. 37771). One of the favorite food fish; meat is considered excellent; eggs are especially priced; made into "som kai pba eum", in which one part of fish eggs with salt and ground rice added is mixed with 15 parts of meat; the uncooked mix is placed in earthen jars to ferment for a number of days before eating (Ref. 12369). In the past, som kai pba eum was eaten mainly in the village where it was made, or occasionally sold at local festivals and celebrations (Ref. 12369). Catch, trade and transportation forbidden under the Fiat-Law on Fishery Management and Administration No. 33 KRO.CHOR of 19 March 1987, as "probatus jullieni". May be caught out of spawning season for local consumption, but cannot legally be caught during the spawning season or traded on a commercial basis at any time under the Lao Ministry of Agriculture and Forestry decree 118/MC 1989, updated 1991 (Ref. 12369). Becoming rare and locally extinct (Ref. 43281). Museum: Mekong at Ban Hang Khone, just below Khone falls, CAS 94159, 95476 (Ref. 5515). Also Ref. 2686, 4792, 7427, 12369, 30857, 36654, 37767, 37770, 44002, 56905. 
Cyprinidae Probarbus labeamajor Roberts, 1992 Fr, Fi, Thr native  Pa eun khao (Laotian), Pba eun khao (Laotian)  150 cm SL male/unsexed  Known from the Mekong River. A strongly migratory species found below the Mun-Chin River to the Khone Falls with declining numbers (Ref. 37772). Reported to migrate upstream during the dry season in December/January in Southern Laos (Ref. 37769). Becoming rare (Ref. 43281). Also Ref. 12255, 12693, 30857, 37767, 37772, 56905. 
Cyprinidae Probarbus labeaminor Roberts, 1992 Fr native   150 cm TL male/unsexed  Known from the Mekong River. Becoming rare (Ref. 43281). Also Ref. 12255. 
Sisoridae Pseudecheneis sympelvica Roberts, 1998 Fr native   5.65 cm SL male/unsexed  Known from the middle Nam Theun (Ref. 43281). Also Ref. 38419.  No picture yet.
Akysidae Pseudobagarius inermis (Ng & Kottelat, 2000) Fr native   3.52 cm SL male/unsexed  Known from the Xe Banghiang and Xe Kong drainages, part of the Mekong River drainage in southern Laos (Ref. 37037). Also Ref. 43281. 
Akysidae Pseudobagarius leucorhynchus (Fowler, 1934) Fr native   3.02 cm SL male/unsexed   
Akysidae Pseudobagarius nitidus (Ng & Rainboth, 2005) Fr native   4.13 cm SL male/unsexed  Known from the Mekong River (Ref. 56231).  No picture yet.
Akysidae Pseudobagarius subtilis (Ng & Kottelat, 1998) Fr native   4.00 cm SL male/unsexed  Found in the Mekong basin at Luang Prabang and Tha Bo (Ref. 30226). Also Ref. 30857. 
Xenocyprididae Pseudohemiculter dispar (Peters, 1881) Fr native   29.10 cm TL male/unsexed  Recorded from Nam Ngay, Nam Ou basin in Phongsali Province (Mekong basin) and from Nam Ma basin in Houaphan Province (Ref. 37786). Possibly introduced in the Mekong basin in Phongsali (Ref. 43281). 
Balitoridae Pseudohomaloptera leonardi (Hora, 1941) Fr native   6.50 cm SL male/unsexed   
Balitoridae Pseudohomaloptera yunnanensis (Chen, 1978) Fr native   5.80 cm SL male/unsexed  Occurs in the middle, lower and upper Xe Bangfai River, a tributary of the Mekong (Ref. 27732). 
Pangasiidae Pseudolais micronemus (Bleeker, 1846) Fr native   100.00 cm male/unsexed  Known from the Mekong basin (Ref. 43281). 
Pangasiidae Pseudolais pleurotaenia (Sauvage, 1878) Fr, Fi native  Nyawn tong khom (Laotian), Pa gnone thong khom (Laotian), Pa nyawn tawng khom (Laotian), Pba nyawn tawng khom (Laotian), Pba nyawn tawng kohm (Laotian)  35.00 cm SL male/unsexed  Known from the Mekong basin (Ref. 43281). Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Collected from Tha Ngon, Island Don Tiane, Tha Bo and Hatsalao of the Mekong basin (Ref. 4792). Observed to undergo migration at the fishing village of Ban Wernsonkhram on Don Hat (Hat Island) above the Lee Pee Waterfalls (Ref. 10431). Also undertakes upstream migration during the wet season in May-July through Hoo Som Yai at the Great Fault Line on the Mekong River, Champassack Province (Ref. 37771). Reported to migrate upstream during the dry season in December/February in Southern Laos (Ref. 37769). Museum: Mekong at Ban Hang Khone, just below Khone falls, CAS 94316 (Ref. 5515). Also Ref. 30857, 36654, 37767, 44002, 56905. 
Bagridae Pseudomystus bomboides Kottelat, 2000 Fr native   4.20 cm SL male/unsexed  Known only from the Nam Mang basin (Ref. 36949). Reported from the Mekong basin (Ref. 43281).  No picture yet.
Bagridae Pseudomystus siamensis (Regan, 1913) Fr native  Pa khi hia (Laotian), Pa kee hia (Laotian), Pba kee hia (Laotian)  18.00 cm TL male/unsexed  Occurs in the Mekong tributaries, the middle Xe Bangfai and the upper Nam Theun basins (Ref. 27732). Collected from Tha Ngon, Tha Bo, Sithan Tay and Khinak (Ref. 4792) and Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Museum: Mekong at Ban Hang Khone, just below Khone falls, CAS 94872 (Ref. 5515). Also Ref. 30857, 36654, 43281. 
Gobionidae Pseudorasbora parva (Temminck & Schlegel, 1846) Fr introduced   12.50 cm TL male/unsexed  Introduced in the Mekong basin in northern Laos (Ref. 43281). 
Siluridae Pterocryptis cochinchinensis (Valenciennes, 1840) Fr native   40.10 cm TL male/unsexed  Occurs in the middle Nam Theun of the Mekong basin (Ref. 27732). Found in the Nam Xam basin (Ref. 43281). Also Ref. 12041. 
Siluridae Pterocryptis inusitata Ng, 1999 Fr native   19.69 cm SL male/unsexed  Known from the middle Nam Theun River drainage (part of the Mekong River drainage). Found in Nam Kading basin (Ref. 43281)  No picture yet.
Nemacheilidae Pteronemacheilus meridionalis (Zhu, 1982) Fr native   6.30 cm SL male/unsexed  Known from the Mekong basin, in Nam Youan, Nam Tha, Nam Ou in northern Laos (Ref. 43281).  No picture yet.
Cyprinidae Puntigrus partipentazona (Fowler, 1934) Fr native  Pa seua noi (Laotian)  6.00 cm TL male/unsexed  Known from the Mekong River. Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 30857, 37786. 
Cyprinidae Puntioplites falcifer Smith, 1929 Fr native  Sagang (Laotian), Pa sakang (Laotian)  40.00 cm male/unsexed  Occurs in the Mekong basin. Found in the lower and middle Xe Bangfai, and the lower Nam Theun basins (Ref. 27732) and Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). In northern Laos, upstream migration occurs in February-May and July-August, but the main period of upstream migration is from March-April; downstream migration takes place in September-November (Ref. 37770). From Champassack in southern Laos to Nakhon Phanom Province in Thailand, upstream migrations occur in May-June and dowstream migrations in November-December (Ref. 37770). Also Ref. 30857, 43281, 44002. 
Cyprinidae Puntioplites proctozystron (Bleeker, 1865) Fr native  Pa sagang (Laotian), Pa sa kang (Laotian), Pba sagang (Laotian)  44.00 cm TL male/unsexed  Occurs in the Mekong basin. Collected from Luang Prabang, Nam Ngum dam site, Tha Ngon, Vientiane, Tha Bo, Sai Fong, Sithan Tay, Pakse, Hatsalao, Bang Lieng (Ref. 4792). Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Enters flooded forest on Don Khone, just below the great waterfalls (Ref. 9497). Also Ref. 36654, 37769, 43281, 45563. 
Cyprinidae Puntioplites waandersi (Bleeker, 1859) Fr native   50.00 cm TL male/unsexed  Occurs in the Mekong basin (Ref. 43281). Also Ref. 7050. 
Cyprinidae Puntius bramoides (Valenciennes, 1842) Fr native   32.50 cm TL male/unsexed  Reported from the Mekong basin.  No picture yet.
Cyprinidae Puntius brevis (Bleeker, 1849) Fr native   14.00 cm TL male/unsexed  Occurs in the middle Xe Bangfai and the middle Nam Theun of the Mekong basin (Ref. 27732). Also Ref. 4792, 7050, 30857, 36654, 43281. 
Danionidae Raiamas guttatus (Day, 1870) Fr native  Pa sanak (Laotian), Pba sanak (Laotian) fairly common (chances are about 50%) 30.00 cm SL male/unsexed  Known from the Mekong basin in the lower and middle Xe Bangfai and the middle Nam Theun rivers (Ref. 27732) and in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Museum: Mekong at Ban Hang Khone, just below Khone falls, CAS 95472 (Ref. 5515). Also Ref. 4792, 9497, 30857, 36654, 43281. 
Danionidae Rasbora amplistriga Kottelat, 2000 Fr native   3.40 cm SL male/unsexed  Presently known from the Mekong basin south of Khone Falls (Ref. 36949). Also Ref. 43281. 
Danionidae Rasbora atridorsalis Kottelat & Chu, 1988 Fr native   8.20 cm SL male/unsexed  Occurs in the middle Xe Bangfai, a tributary of the Mekong (Ref. 27732). Also Ref. 43281. 
Danionidae Rasbora aurotaenia Tirant, 1885 Fr native   15.00 cm SL male/unsexed  Occurs in the Mekong River (Ref. 43281). Also Ref. 30857. 
Danionidae Rasbora borapetensis Smith, 1934 Fr native  Pa sieu (Laotian)  10.00 cm TL male/unsexed  Occurs in the Mekong basin (Ref.43281). Found in the middle Xe Bangfai River (Ref. 27732), Tha Ngon, Tha Bo, Sithan Tay, Pakse, Hatsalao and Pathoum Phon of the Mekong basin (Ref. 4792). Also Ref. 30857, 36654. 
Danionidae Rasbora daniconius (Hamilton, 1822) Fr native   15.00 cm TL male/unsexed  Known from the Mekong basin. Found in the middle Xe Bangfai (Ref. 27732) and Tha Ngon in the Mekong basin (Ref. 4792). Also Ref. 30857, 36654. 
Danionidae Rasbora dorsinotata Kottelat, 1987 Fr native   4.32 cm SL male/unsexed  Known from the Mekong basin (Ref. 43281) in Nam Ma Oun, Louang Na Tha Province (Ref. 37786).  No picture yet.
Danionidae Rasbora dusonensis (Bleeker, 1850) Fr native  Pa sieu (Laotian)  12.00 cm SL male/unsexed  Known from the Mekong tributaries in the lower and middle Xe Bangfai (Ref. 27732). Also Ref. 4792, 36654. 
Danionidae Rasbora hobelmani Kottelat, 1984 Fr native   6.00 cm SL male/unsexed  Known from the Mekong River (Ref. 43281). Recorded from Nam Mao, Oudomxai Province (Ref. 37786). Also Ref. 30857. 
Danionidae Rasbora myersi Brittan, 1954 Fr native   7.29 cm SL male/unsexed  Known from the Xe Bangfai drainage (Ref. 93740). 
Danionidae Rasbora paucisqualis Ahl, 1935 Fr native   4.00 cm SL male/unsexed   
Danionidae Rasbora paviana Tirant, 1885 Fr native   12.00 cm SL male/unsexed  Known from the Mekong River (Ref. 43281) in the middle Xe Bangfai and the middle Nam Theun (Ref. 27732). Museum: Mekong river at Ban Hang Khone, just below Khone falls, CAS 94903 (Ref. 5515). Also Ref. 30857. 
Danionidae Rasbora rubrodorsalis Donoso-Büchner & Schmidt, 1997 Fr native   3.30 cm SL male/unsexed   
Danionidae Rasbora septentrionalis Kottelat, 2000 Fr native   5.70 cm SL male/unsexed  Presently known only from the Nam Youan basin (Mekong) (Ref. 36949). Also Ref. 43281. 
Danionidae Rasbora steineri Nichols & Pope, 1927 Fr native   10.00 cm TL male/unsexed  Known from the Nam Ma basin. 
Danionidae Rasbora sumatrana (Bleeker, 1852) Fr native   13.00 cm TL male/unsexed  Known from the Mekong basin at Tha Ngon and Sithan Tay. Also Ref. 36654. 
Danionidae Rasbora tornieri Ahl, 1922 Fr native   17.00 cm SL male/unsexed   
Danionidae Rasbora trilineata Steindachner, 1870 Fr native   13.00 cm TL male/unsexed  Occurs in the middle Xe Bangfai of the Mekong basin (Ref. 27732). Collected from Tha Ngon, Tha Bo and Sai Fong in the Mekong basin (Ref. 4792). Also Ref. 30857, 36654, 43281. 
Danionidae Rasbosoma spilocerca (Rainboth & Kottelat, 1987) Fr native   2.60 cm SL male/unsexed  Known from the Mekong River (Ref. 43281). Also Ref. 30857. 
Gobiidae Rhinogobius albimaculatus Chen, Kottelat & Miller, 1999 Fr native   5.90 cm TL male/unsexed  Recorded from the Nam San basin in the Mekong basin (Ref. 33279). Found in Houay Sala Yai, a tributary of Nam San, 18° 35 ' 17" N, 103° 5' 0" E, Mekong basin, Vientiane province (Ref. 33021). Also Ref. 43281.  No picture yet.
Gobiidae Rhinogobius honghensis Chen, Yang & Chen, 1999 Fr native   4.50 cm SL male/unsexed  Known from the Nam Xam basin (Ref. 43281).  No picture yet.
Gobiidae Rhinogobius leavelli (Herre, 1935) Fr native   8.80 cm SL male/unsexed  Occurs in the Nam Ma and Nam Mat basins (Ref. 43281).  No picture yet.
Gobiidae Rhinogobius lineatus Chen, Kottelat & Miller, 1999 Fr native   3.82 cm SL male/unsexed  Collected only in the lower Nam Theun and in the Nam Gnouang, a tributary of the Nam Theung, downriver of Ban Thabak, 18° 16' 50"N, 104°38'0" (Ref. 33021) in the Mekong basin of Laos, Bolikhamxai Prov. (Ref. 33279). Also Ref. 43281.  No picture yet.
Gobiidae Rhinogobius maculicervix Chen & Kottelat, 2000 Fr native   4.19 cm SL male/unsexed  Known from the Mekong basin in the Nam Youan drainage, northern Laos. Also Ref. 43281.  No picture yet.
Gobiidae Rhinogobius mekongianus (Pellegrin & Fang, 1940) Fr native   5.00 cm SL male/unsexed  Known from the lower and middle Nam Theun of the Mekong basin (Ref. 27732). Also Ref. 4792, 12693, 30857, 43281 
Gobiidae Rhinogobius milleri Chen & Kottelat, 2001 Fr native   4.60 cm SL male/unsexed  Occurs in Nam Mat and Nam Mo basins (Ref. 43281).  No picture yet.
Gobiidae Rhinogobius nammaensis Chen & Kottelat, 2001 Fr native   4.30 cm SL male/unsexed  Occurs in the Nam Ma basin (Ref. 43281).  No picture yet.
Gobiidae Rhinogobius taenigena Chen, Kottelat & Miller, 1999 Fr native   3.10 cm SL male/unsexed  Collected from Xe Pon between rapids upstream and downstream of Ban Fuang, Xe Bang Hiang basin, Mekong Basin, Savannakhet Prov., type locality (Ref. 33279). Also Ref. 43281.  No picture yet.
Gobiidae Rhinogobius vermiculatus Chen & Kottelat, 2001 Fr native   3.50 cm SL male/unsexed  Occurs in the Nam Xam basin (Ref. 43281).  No picture yet.
Acheilognathidae Rhodeus laoensis Kottelat, Doi & Musikasinthorn, 1998 Fr native   4.69 cm SL male/unsexed  Occurs in the middle Nam Theun, a tributary of the Mekong basin (Ref. 27732). Also Ref. 43281.  No picture yet.
Gobionidae Sarcocheilichthys hainanensis Nichols & Pope, 1927 Fr native   9.00 cm SL male/unsexed  Known from Nam Ma basin (Ref. 43281).  No picture yet.
Cyprinidae Scaphiodonichthys acanthopterus (Fowler, 1934) Fr native   31.00 cm SL male/unsexed  Known from the Mekong basin. Occurs in the upper, middle and lower Nam Theun and the upper Xe Bangfai (Ref. 27732). Also Ref. 4792, 30857. 
Cyprinidae Scaphiodonichthys burmanicus Vinciguerra, 1890 Fr native   22.00 cm TL male/unsexed   
Cyprinidae Scaphognathops bandanensis Boonyaratpalin & Srirungroj, 1971 Fr, Fi native  Pa pian (Laotian), Pa pien (Laotian), Pba pian (Laotian), Pba pien (Laotian), Pien 9 (Laotian)  40.00 cm SL male/unsexed  Known from the Mekong basin. Found in the middle Xe Bangfai (Ref. 27732) and Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Occurs in deep slow reaches during dry season in the Mekong basin at Muang Khong (Ref. 37769). Undertakes an upstream non-reproductive migration in December-March at Hat Village, Muang Khong (Ref. 37769 ). Observed to undergo migration and fished heavily at the fishing village of Ban Wernsonkhram on Don Hat (Hat Island) above the Lee Pee Waterfalls (Ref. 10431). Museum: Mekong at Ban Hang Khone, just below Khone falls, CAS 94886, 95436 (Ref. 5515). Also Ref. 30857, 36654, 37767, 56905. 
Cyprinidae Scaphognathops stejnegeri (Smith, 1931) Fr, Fi native  Pa pien (Laotian), Pa pian (Laotian), Pba pian (Laotian), Pba pien (Laotian), Pien 13 (Laotian)  25.00 cm SL male/unsexed  Known from the Mekong basin. Found in the middle Xe Bangfai (Ref. 27732) and Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Occurs during dry season in deep slow reaches of the Mekong basin at Muang Khong (Ref. 37769). Migrates upstream in December-March and appears to engage in two separate types of migration at Hat Village, Muang Khong: the first an upstream reproductive migration arriving in the Muang Khong area in late December and early January and the second, a post-spawning movement which may have a trophic component (Ref. 37769). Observed to undergo migration and fished heavily at the fishing village of Ban Wernsonkhram on Don Hat (Hat Island) above the Lee Pee Waterfalls (Ref. 10431). Also Ref. 4792, 30857, 36654, 37767, 56905. 
Cyprinidae Scaphognathops theunensis Kottelat, 1998 Fr native   30.00 cm SL male/unsexed  Occurs in the middle and lower Nam Theun, a tributary of the Mekong (Ref. 27732). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura albisella Kottelat, 2017 Fr native   4.37 cm SL male/unsexed  Currently found only in small tributaries of the Nam Ngiep near Ban Soppouan and Ban Sopyouak (Ref. 117204).  No picture yet.
Nemacheilidae Schistura amplizona Kottelat, 2000 Fr native   9.09 cm SL male/unsexed  Known only from the Nam Tha and Nam Youan basins of the Mekong in northern Laos (Ref. 36949). Also Ref. 43281, 95066.  No picture yet.
Nemacheilidae Schistura aramis Kottelat, 2000 Fr native   7.10 cm SL male/unsexed  Known from a simgle stream near Muang Mai, in the Nam Nua basin, a tributary of the Nam Ou (ref. 36949). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura athos Kottelat, 2000 Fr native   9.00 cm SL male/unsexed  Known only from the Nam Ou basin in northern Laos (Ref. 36949).  No picture yet.
Nemacheilidae Schistura atra Kottelat, 1998 Fr native   5.10 cm SL male/unsexed  Occurs in the middle and upper Nam Theun, a tributary of the Mekong (Ref. 27732). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura bairdi Kottelat, 2000 Fr native   3.20 cm SL male/unsexed  Occurs in the Mekong mainstream downriver of Khone Falls (Ref. 36949). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura bolavenensis Kottelat, 2000 Fr endemic   8.80 cm SL male/unsexed  Occurs in the tributaries of the Xe Kong and Xe Don of the Mekong basin on Bolaven Plateau (Ref. 36949). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura bucculenta (Smith, 1945) Fr native   10.40 cm SL male/unsexed  Reported from the Mekong basin (Ref. 4792). Occurs in Nam Ou and Nam Tha basins and northeastern Xaignabouli Province (Ref. 43281). Found in Huey Nam Puat at Ban Nam Puat (Ref. 39226). Also Ref. 12041. 
Nemacheilidae Schistura cataracta Kottelat, 1998 Fr native   6.70 cm SL male/unsexed  Occurs in the middle and upper Nam Theun, a tributary of the Mekong (Ref. 27732), Nam Kading and Xe Banghiang basins (Ref. 43281).  No picture yet.
Nemacheilidae Schistura caudofurca (Mai, 1978) Fr native   8.10 cm SL male/unsexed  Known from Nam Mat, Nam Xam, and Nam Ma basins (Ref. 43281).  No picture yet.
Nemacheilidae Schistura clatrata Kottelat, 2000 Fr native   6.59 cm SL male/unsexed  Occurs in the Xe Kong of the Mekong basin (Ref. 36949). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura colossa Kottelat, 2017 Fr native   9.80 cm SL male/unsexed  Known from the Bolaven Plateau in the Xe Pian drainage, a tributary of the Xe Kong, in southern Laos (Ref. 117207).  No picture yet.
Nemacheilidae Schistura coruscans Kottelat, 2000 Fr native   6.60 cm SL male/unsexed  Occurs in the lower and middle Nam San basin, a tributary of Nam Ngum of the Mekong basin (Ref. 36949). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura crabro Kottelat, 2000 Fr native   3.00 cm SL male/unsexed  Known only from the holotype, part of material from mixed localities in the Nam Ngiap basin (Ref. 36949). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura crassa Kottelat, 2017 Fr native   5.65 cm SL male/unsexed  Known so far from the middle Nam Ngiep. The downstream and upstream of the Nam Ngiep have not been sampled yet (Ref. 1177204).  No picture yet.
Nemacheilidae Schistura daubentoni Kottelat, 1990 Fr native   3.50 cm SL male/unsexed  Occurs in the Mekong basin. Found in the middle Xe Bangfai River, a tributary of the Mekong (Ref. 27732). Also Ref. 43281. 
Nemacheilidae Schistura defectiva Kottelat, 2000 Fr native   4.85 cm SL male/unsexed  Occurs in Nam Ngum and Nam Khan basins of the Mekong (Ref. 36949). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura dorsizona Kottelat, 1998 Fr native   4.30 cm SL male/unsexed 4.02 SL Occurs in the lower and upper Nam Theun, a tributary of the Mekong basin (Ref. 27732). Also Ref. 43281. 
Nemacheilidae Schistura ephelis Kottelat, 2000 Fr native   8.19 cm SL male/unsexed  Occurs in the lower and upper Nam San basin, a tributary of Nam Ngum of the Mekong basin (Ref. 36949). Also Ref. 43281. 
Nemacheilidae Schistura epixenos Kottelat, 2017 Fr native   5.95 cm SL male/unsexed  Currently found only in the Nam Kathang Gnai [also spelt Katang Yai] on the Nakai Plateau (Ref. 117206).  No picture yet.
Nemacheilidae Schistura finis Kottelat, 2000 Fr native   9.00 cm SL male/unsexed  Only known from the type locality, a small creek in the Nam Mo basin making the border between Laos and Vietnam (Ref. 36949). Also Ref. 43281, 44416.  No picture yet.
Nemacheilidae Schistura fusinotata Kottelat, 2000 Fr native   4.30 cm SL male/unsexed  Known only from the Xe Kong basin of the Mekong (Ref. 36949). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura globiceps Kottelat, 2000 Fr native   5.30 cm SL male/unsexed  Known only from the type locality, a small forest creek along the water divide between the Nam Tha and Nam Ou basins (Ref. 36949). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura imitator Kottelat, 2000 Fr native   4.49 cm SL male/unsexed  Known only from the Xe Kong of the Mekong basin (Ref. 36949). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura implicata Kottelat, 2000 Fr native   8.69 cm SL male/unsexed  Found in Nam Luong basin, a southern tributary of the Nam Ma east of Viangxai entering it in Vietnam (Ref. 36949). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura irregularis Kottelat, 2000 Fr native   8.60 cm SL male/unsexed  Known only from the Nam Khan of the Mekong basin (Ref. 36949). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura isostigma Kottelat, 1998 Fr native   2.60 cm SL male/unsexed  Occurs in the middle Xe Bangfai, a tributary of the Mekong basin (Ref. 27732). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura kaysonei Vidthayanon & Jaruthanin, 2002 Fr native    Type locality, Phu Tham Nam cave, Ban (village) Don Yom in Khammouan karst, between lat. 18°45'N, 104°45'E and 18°30'N, 105°00'E (Ref. 46206). 
Nemacheilidae Schistura kengtungensis (Fowler, 1936) Fr native   11.00 cm SL male/unsexed  Occurs in Nam Ou (Ref. 36949), Nam Beng, Nam Tha and Nam Youan basins (Ref. 43281). Listed as Schistura cf. kengtungensis in Ref. 30857. 
Nemacheilidae Schistura khamtanhi Kottelat, 2000 Fr native   6.10 cm SL male/unsexed  Known only from the Xe Kong basin and the Mekong at Khone Falls (Ref. 36949). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura kloetzliae Kottelat, 2000 Fr native   5.00 cm SL male/unsexed  Known from the Mengla basin (Ref. 36949). Found in the Nam Youan basin (Ref. 43281).  No picture yet.
Nemacheilidae Schistura klydonion Kottelat, 2017 Fr native   7.60 cm SL male/unsexed  Known only from the Xe Namnoy on the Bolaven Plateau in southern Laos (Ref. 117207).  No picture yet.
Nemacheilidae Schistura kongphengi Kottelat, 1998 Fr native   9.07 cm SL male/unsexed  Occurs in the lower, middle and upper Nam Theun, a tributary of the Mekong basin (not collected on Nakay Plateau) (Ref. 27732). Found in Nam Kading, Xe Banghiang and Xe Kong basins (Ref. 43281).  No picture yet.
Nemacheilidae Schistura latidens Kottelat, 2000 Fr native   5.78 cm SL male/unsexed  Known only from the type locality, in the middle Xe Pon basin (Ref. 36949). Found in Xe Banghiang basin (Ref. 43281).  No picture yet.
Nemacheilidae Schistura leukensis Kottelat, 2000 Fr native   5.80 cm SL male/unsexed  Occurs in Nam Leuk, a tributary of Nam Mang (ref. 36949). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura macrocephalus Kottelat, 2000 Fr native   8.40 cm SL male/unsexed  Known from the Nam Youan basin (Ref. 36949). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura magnifluvis Kottelat, 1990 Fr native   8.50 cm SL male/unsexed  Known from the Mekong basin (Ref. 43281). 
Nemacheilidae Schistura melarancia Kottelat, 2000 Fr endemic   9.60 cm SL male/unsexed  Apparently endemic to the Nam Ou basin in northern Laos (Ref. 36949). Also Ref. 43281, 92804.  No picture yet.
Nemacheilidae Schistura musa Kottelat, 2017 Fr native   4.23 cm SL male/unsexed  Known so far from the middle Nam Ngiep (Ref. 117204).  No picture yet.
Nemacheilidae Schistura nicholsi (Smith, 1933) Fr native   7.40 cm SL male/unsexed  Known from the Mekong basin. Found in the middle Xe Bangfai River, a tributary of the Mekong (Ref. 27732). Listed as Schistura cf. nicholsi in Ref. 30857. Also Ref. 43281. 
Nemacheilidae Schistura nomi Kottelat, 2000 Fr native   4.76 cm SL male/unsexed  Known only from the Xe Kamang in the Mekong basin (Ref. 36949). Found in the Xe Kong basin (Ref. 43281).  No picture yet.
Nemacheilidae Schistura novemradiata Kottelat, 2000 Fr native   5.68 cm SL male/unsexed  Known only from Nam Tha basin in northern Laos (Ref. 36949). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura nudidorsum Kottelat, 1998 Fr native   7.50 cm SL male/unsexed  Occurs in the lower and upper Nam Theun, a tributary of the Mekong (Ref. 27732). Collected from Nam Kading and Xe Banghiang basins (Ref. 43281).  No picture yet.
Nemacheilidae Schistura obeini Kottelat, 1998 Fr native   10.50 cm SL male/unsexed  Occurs in the lower, middle and upper Nam Theun, a tributary of the Mekong (Ref. 27732). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura personata Kottelat, 2000 Fr native   6.06 cm SL male/unsexed  Known only from the Nam San, a tributary of the Nam Ngum (Ref. 36949). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura pertica Kottelat, 2000 Fr native   6.56 cm SL male/unsexed  Known from the type locality, in the Nam Ou basin (Ref. 36949). Expected to occur in Nam Youan basins (Ref. 43281).  No picture yet.
Nemacheilidae Schistura pervagata Kottelat, 2000 Fr native  common (usually seen) 8.03 cm SL male/unsexed  Found in Nam Ma basin (Ref. 36949). Also Ref. 43281, 40772  No picture yet.
Nemacheilidae Schistura poculi (Smith, 1945) Fr native   5.90 cm SL male/unsexed  Occurs in the Mekong basin (Ref. 43281). 
Nemacheilidae Schistura porthos Kottelat, 2000 Fr native   8.60 cm SL male/unsexed  Known only from Nam Ngiap, Nam Khan, Nam Xuang, Nam Ou and Nam Tha basins of the Mekong, northern Laos (Ref. 36949). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura procera Kottelat, 2000 Fr native   8.90 cm SL male/unsexed  Known only from the type locality, a small creek at the foot of a waterfall in forest, in the Nam Ou basin (Ref. 36949). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura punctifasciata Kottelat, 1998 Fr native   3.30 cm SL male/unsexed  Occurs in the middle Xe Bangfai, a tributary of the Mekong (Ref. 27732). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura quaesita Kottelat, 2000 Fr native   5.40 cm SL male/unsexed  Known only from the type locality, the upper Nam Ngum (Ref. 36949). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura quasimodo Kottelat, 2000 Fr native   4.90 cm SL male/unsexed  Known from the lower and upper Nam San basin, a Nam Ngum tributary (Ref. 36949). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura rikiki Kottelat, 2000 Fr native   2.50 cm SL male/unsexed  Occurs in the Xe Kong and Xe Kaman main rivers (Ref. 36949). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura russa Kottelat, 2000 Fr native   5.00 cm SL male/unsexed  Known only from the upper Nam Tha basin of the Mekong (Ref. 36949). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura schultzi (Smith, 1945) Fr native   9.30 cm SL male/unsexed  Known from the Mekong basin (Ref. 43281). 
Nemacheilidae Schistura sertata Kottelat, 2000 Fr native   5.28 cm SL male/unsexed  Known only from the type locality, Kuang Xi waterfall near Louang Phabang, Mekong (Ref. 36949). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura sigillata Kottelat, 2000 Fr native   4.59 cm SL male/unsexed  Occurs in Nam San, a tributary of Nam Ngum, and Nam Ngiap basins (Ref. 36949). Also Ref. 43281. 
Nemacheilidae Schistura sombooni Kottelat, 1998 Fr native   6.50 cm SL male/unsexed 5.72 SL Occurs in the lower, middle and upper Nam Theun, a tributary of the Mekong (Ref. 27732). Found in Nam Kading, Nam Ngiap and Nam Ngum basins (Ref. 43281).  No picture yet.
Nemacheilidae Schistura spiloptera (Valenciennes, 1846) Fr questionable   5.22 cm SL male/unsexed  Reported from the Mekong basin (Ref. 4792). Outside distributional range, occurrence needs confirmation. 
Nemacheilidae Schistura suber Kottelat, 2000 Fr native   2.97 cm SL male/unsexed  Known from the upper Nam Leuk basin (Ref. 36949). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura tenura Kottelat, 2000 Fr native   4.70 cm SL male/unsexed  Known only from upper Nam Leuk basin, a tributary of the Nam Mang (Ref. 36949). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura thavonei Kottelat, 2017 Fr native   4.76 cm SL male/unsexed  Currently found only in Nam Ma watershed in Louang Namtha Province, a tributary of the Mekong, in northeastern Laos (different from Nam Ma in Houa Phan Province (Ref. 117218).  No picture yet.
Nemacheilidae Schistura tizardi Kottelat, 2000 Fr native   4.90 cm SL male/unsexed  Occurs in the Mekong at the Xe Kong basin (Ref. 36949). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura tubulinaris Kottelat, 1998 Fr native   6.10 cm SL male/unsexed 5.31 SL Occurs in the middle and upper Nam Theun, a tributary of the Mekong (Ref. 27732). Also Ref. 43281.  No picture yet.
Nemacheilidae Schistura xhatensis Kottelat, 2000 Fr native   3.86 cm SL male/unsexed  Known only from the type locality, the Nam Xhat, a tributary of the Nam Khan (Ref. 36949). Also Ref. 43281.  No picture yet.
Scombridae Scomberomorus sinensis (Lacepède, 1800) Fr, Br native  occasional (usually not seen) 247 cm TL male/unsexed  A marine species that ascends the Mekong River to the Khoné Falls. Large individuals are seen during the dry season in the fast flowing Mekong from Khoné to Kratie (Ref. 12693). Also Ref. 30857, 43281. 
Nemacheilidae Sectoria heterognathos (Chen, 1999) Fr native   10.00 cm SL male/unsexed  Occurs in the Nam Youan basin (Ref. 43281).  No picture yet.
Serpenticobitidae Serpenticobitis cingulata Roberts, 1997 Fr native   3.86 cm SL male/unsexed  Known from the Mekong basin in northern Laos (Ref. 43281).  No picture yet.
Serpenticobitidae Serpenticobitis octozona Roberts, 1997 Fr native   5.40 cm SL male/unsexed  Occurs in the Sekong watershed of the lower Mekong basin. Collected at Xe Nam Noi, Xe Pian, Houay Samang and Se Kaman (Ref. 38649). Type locality, Xe Nam Noi on eastern slope of Bolaven Plateau, ca. 30 km from Ban Nam Tang, Attapeu Prov., 130 m elev (Ref. 33021). Also Ref. 43281. 
Serpenticobitidae Serpenticobitis zonata Kottelat, 1998 Fr native   4.30 cm SL male/unsexed  Occurs in the middle Xe Bangfai basin, a tributary of the Mekong (Ref. 27732) and Xe Bang Hiang (Ref. 43281). 
Engraulidae Setipinna melanochir (Bleeker, 1849) Fr, Br, Thr native  Pa maeo (Laotian), Pa mak jan (Laotian)  33.00 cm SL male/unsexed  Known from the Mekong basin dowstream of Khone Falls (Ref. 43281). Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Museum: Mekong, CAS 94778 (Ban Hang Khan Khone, just below Khone falls); CAS 93474 (below Khone falls) (Ref. 5515). Also Ref. 30857, 37767. 
Gastromyzontidae Sewellia diardi Roberts, 1998 Fr native   7.18 cm SL male/unsexed  Known from the hill streams in Se Kong watershed, a tributary of the Mekong basin (Ref. 38650). Collected in the lower part of the River Xe Nam Noi, middle part of the River Xe Pian and in the River Houai Sai; all in the Se Kong drainage (Ref. 40433). Also Ref. 40433, 43281.  No picture yet.
Gastromyzontidae Sewellia elongata Roberts, 1998 Fr native   7.30 cm SL male/unsexed  Known from the Se Kong watershed (tributary of the Mekong basin) where it is found only in the upper reaches of the Xe Nam Noi and adjacent Xe Pian on the Bolovens plateau in southern Laos. Also Ref. 40433, 43281.  No picture yet.
Gastromyzontidae Sewellia speciosa Roberts, 1998 Fr native   5.37 cm SL male/unsexed  Known from the lower Xe Nam Noi, middle section of the River Xe Pian, a stream running into the River Se Kaman and in the River Houai Sai, all in the Se Kong drainage in southern Laos (Ref. 40433). Also Ref. 43281. 
Cyprinidae Sikukia flavicaudata Chu & Chen, 1987 Fr native   15.00 cm SL male/unsexed  Occurs in the Mekong basin.  No picture yet.
Cyprinidae Sikukia gudgeri (Smith, 1934) Fr native  Pa khao na (Laotian), Pa mang (Laotian) abundant (always seen in some numbers) 18.00 cm SL male/unsexed  Occurs in the Mekong basin. Found in the lower and middle Xe Bangfai of the Mekong basin (Ref. 27732) and Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 4792, 12693, 30857, 37768. 
Cyprinidae Sikukia stejnegeri Smith, 1931 Fr native   12.00 cm TL male/unsexed  Occurs in the Mekong basin (Ref. 43281). Also Ref. 36654, 37768. 
Odontobutidae Sineleotris namxamensis Chen & Kottelat, 2004 Fr native   8.00 cm SL male/unsexed  Occurs in the Nam Xam basin (Ref. 43281).  No picture yet.
Botiidae Sinibotia longiventralis (Yang & Chen, 1992) Fr native   10.55 cm SL male/unsexed  Occurs in the Mekong basin in Louang Phabang (Ref. 43281). Recorded from Luang Prabang market (Ref. 37786). 
Xenocyprididae Sinibrama melrosei (Nichols & Pope, 1927) Fr native   18.30 cm SL male/unsexed  Occurs in the Nam Ma basin (Ref. 43281). 
Cyprinidae Speolabeo musaei (Kottelat & Steiner, 2011) Fr native   7.74 cm SL male/unsexed  Found in caves of the Xe Bangfai drainage (tributary of Mekong) in Central Laos (Ref. 86533).  No picture yet.
Cyprinidae Spinibarbus caldwelli (Nichols, 1925) Fr native   32.50 cm SL male/unsexed  Found in the Nam Ma and Nam Mat basins. 
Cyprinidae Spinibarbus denticulatus (Oshima, 1926) Fr native   41.50 cm SL male/unsexed  Occurs in the Nam Ma basin (Ref. 43281). 
Gobionidae Squalidus atromaculatus (Nichols & Pope, 1927) Fr native   11.00 cm TL male/unsexed  Occurs in the Nam Ma basin (Ref. 43281).  No picture yet.
Ehiravidae Sundasalanx mekongensis Britz & Kottelat, 1999 Fr native   2.78 cm SL male/unsexed  Known from the middle Mekong and its main tributaries from Vientaine to Savannakhet (Ref. 38648). Also Ref. 43281, 94476.  No picture yet.
Ehiravidae Sundasalanx microps Roberts, 1981 Fr questionable   2.30 cm TL male/unsexed  Recorded from the Mekong basin, including the lower Xe Bangfai basin. This species is known from the Kapuas basin, Borneo; thus, a more detailed comparison is needed to confirm that they are conspecific. Listed as Sundasalanx aff. microps. 
Ehiravidae Sundasalanx praecox Roberts, 1981 Fr native   2.25 cm SL male/unsexed   
Botiidae Syncrossus beauforti (Smith, 1931) Fr native  Pa kieo kai (Laotian)  25.00 cm SL male/unsexed  Occurs in the Mekong basin (Ref. 43281). Found in the Mekong tributaries in the lower, middle and upper Xe Bangfai (Ref. 27732). Questionably from the Nam Theun basin. Also Ref. 4792, 30857, 36654. 
Botiidae Syncrossus helodes (Sauvage, 1876) Fr native  Pa kheo kai (Laotian), Pba moo mun (Laotian)  30.00 cm SL male/unsexed  Occurs in the lower Xe Bangfai, a tributary of the Mekong basin (Ref. 27732). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Museum: Mekong river at Ban Hang Khone, just below Khone Falls, CAS 92913 (Ref. 5515). Also Ref. 30857, 36654, 50526. 
Cyprinidae Systomus jacobusboehlkei (Fowler, 1958) Fr native   12.00 cm SL male/unsexed  Occurs in the lower and middle Xe Bangfai of the Mekong basin (Ref. 27732). Also Ref. 43281. 
Cyprinidae Systomus rubripinnis (Valenciennes, 1842) Fr, Fi native  Pok (Laotian), Pa pohk (Laotian), Pa pok (Laotian) fairly common (chances are about 50%) 25.00 cm SL male/unsexed  Known from the Mekong basin. Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Recent decline in fisheries probably due to "lee" (see Puntius altus). Also Ref. 4792, 30857, 36654, 37767, 43281, 56905. 
Bagridae Tachysurus fulvidraco (Richardson, 1846) Fr native   34.50 cm TL male/unsexed  Found in Nam Ma basin (Ref. 43281). 
Dorosomatidae Tenualosa thibaudeaui (Durand, 1940) Fr, Fi native  Pa mak phang (Laotian), Mak pang (Laotian), Pa mak pang (Laotian), Pba mak pang (Laotian) scarce (very unlikely) 30.00 cm SL male/unsexed  Known from the Mekong basin (Ref. 43281). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Formerly the most abundant of all fish species in the Mekong at Ban Hang Khone. The species has declined steadily since 1970 until now it is relatively rare, no large scale migrations have been observed for about ten years, and is considered by fisherfolk to most likely disappear (Ref. 9497). The most successful fishermen in Ban Hang Khone reported he caught 400-500 kg yearly during the entire January-February migratory period in the 1970s. His catch declined to 20-30 kg over a 10 day-period in February about 10 years ago (1984?) (Ref. 12369). Reported to migrate upstream above the Khone Falls from March to June (Ref. 37770). The combination of the first rain, increased water levels and increased turbidity are the main factors that trigger upstream migration (Ref. 37770). Museum: Mekong below Khone falls, CAS 96773; Mekong at Ban Hang Khone, just below Khone falls, CAS 96873 (Ref. 5515). Also Ref. 188, 12693, 30857, 37772, 44002, 56905. 
Odontobutidae Terateleotris aspro (Kottelat, 1998) Fr native   10.00 cm SL male/unsexed  Occurs in the middle Xe Bangfai, a tributary of the Mekong (Ref. 27732). Also Ref. 43281, 42922, 92840.  No picture yet.
Cyprinidae Thynnichthys thynnoides (Bleeker, 1852) Fr native  Pa koum (Laotian), Pa goom (Laotian), Pa keum (Laotian)  25.00 cm TL male/unsexed  Known from the Mekong River (Ref. 43281). Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Collected from Tha Ngon, Vientiane, Tha Bo, Khouai Deng (Ref. 4792). Museum: Mekong at Ban Hang Khone, just below Khone falls, CAS 96961 (Ref. 5515). Also Ref. 4792, 30857, 36654, 37767, 37769. 
Cyprinidae Tor ater Roberts, 1999 Fr native  scarce (very unlikely) 33.20 cm SL male/unsexed  Known only from the three type specimens collected at Ban Talang in Nam Theun watershed (Mekong basin). Recorded from Nam Kading basin (Ref. 43281).  No picture yet.
Cyprinidae Tor douronensis (Valenciennes, 1842) Fr native  Pa hien (Laotian)  35.00 cm TL male/unsexed  Known from the Mekong River. Also Ref. 7050, 13848. 
Cyprinidae Tor laterivittatus Zhou & Cui, 1996 Fr native   60.00 cm SL male/unsexed  Occurs in the upper Xe Bangfai and the lower, middle and upper Nam Theun basins (tributaries of the Mekong). Also Ref. 43281. 
Cyprinidae Tor sinensis Wu, 1977 Fr native  Pba daeng (Laotian)  46.50 cm SL male/unsexed  Known from Se Kong, upper Nam Ngum, Nam Hinboun, Xe Bang Fai and Nam Theun of the Mekong basin. Reported to undergo upstream reproductive migrations in the mainstream and larger tributaries of the Nam Theun in large numbers that the rivers turn red. In the Se Kong, as elsewhere in Laos, juveniles often occur sympatrically with T. tambra (Ref. 35913). Also Ref. 30857 (listed as Tor cf. sinensis). 
Cyprinidae Tor tambra (Valenciennes, 1842) Fr native  Pba tohn (Laotian), Pba gwa (Laotian), Pba tohn (Laotian)  100.00 cm TL male/unsexed  Known from Se Kong and Nam Theum watersheds of the Mekong basin. Also Ref. 4792, 43281. 
Cyprinidae Tor tambroides (Bleeker, 1854) Fr native  Pa kva (Laotian)  100.00 cm SL male/unsexed  Occurs in the lower and middle Nam Theun, tributary of the Mekong basin (Ref. 27732). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 4792, 7050, 30857. 
Toxotidae Toxotes chatareus (Hamilton, 1822) Fr native  Pa mong (Laotian)  40.00 cm SL male/unsexed  Known from the Mekong basin (Ref. 43281). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 12693, 30857. 
Toxotidae Toxotes microlepis Günther, 1860 Fr native  Pa meo (Laotian)  15.00 cm SL male/unsexed  Occurs in the Mekong and the lower Xe Bangfai (Ref. 27732). Recorded from Ban Hang Sadam (Ref. 44002). Also Ref. 4792, 30857. 
Nemacheilidae Traccatichthys taeniatus (Pellegrin & Chevey, 1936) Fr native   10.50 cm SL male/unsexed  Occurs in the Nam Xam basin (Ref. 43281) and Ma River basin (Ref. 40772).  No picture yet.
Osphronemidae Trichopodus pectoralis Regan, 1910 Fr, Fi native  Pa sa lit (Laotian)  25.00 cm TL male/unsexed  Occurs in the Mekong basin (Ref. 43281). Found in the Khone Falls (Ref. 37772). Also Ref. 2686, 4792, 30857, 36654, 56905. 
Osphronemidae Trichopodus trichopterus (Pallas, 1770) Fr, Fi native  Pa salid (Laotian), Pa ka dout (Laotian)  15.00 cm SL male/unsexed  Known from the Mekong basin in the middle Xe Bangfai river (Ref. 27732) and in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls at Lee Pee (Ref. 9497). Also Ref. 4792, 30857, 36654, 43281. 
Osphronemidae Trichopsis pumila (Arnold, 1936) Fr native   4.00 cm SL male/unsexed   
Osphronemidae Trichopsis schalleri Ladiges, 1962 Fr native   5.00 cm SL male/unsexed  Occurs in the middle Nam Theun of the Mekong basin (Ref. 27732). Also Ref. 43281. 
Osphronemidae Trichopsis vittata (Cuvier, 1831) Fr native  Pa maht (Laotian), Pa mat (Laotian)  8.00 cm TL male/unsexed  Known from the Mekong basin (Ref. 30857). Found in Ban Hang Khone at Don Khone, 3 km below the fall line of the great waterfalls of the Mekong basin at Lee Pee (Ref. 9497). Also Ref. 4792, 36654, 37767, 43281, 50526. 
Danionidae Trigonostigma espei (Meinken, 1967) Fr native   2.50 cm SL male/unsexed   
Cyprinidae Troglocyclocheilus khammouanensis Kottelat & Bréhier, 1999 Fr native  Paa kham khom (Laotian)  4.00 cm SL male/unsexed  Known from Khammouan Karst east of Thakhek; in caves (Ref. 43281). Type locality, Khoung Nam Dôn, resurgence of Nam Dôn [stream] near Ban Phôndou [village], 17°33'50"N, 104°52'20"E, Khammouan Prov. (Ref. 44096). Also Ref. 44736.  No picture yet.
Dasyatidae Urogymnus polylepis (Bleeker, 1852) Fr native  Fa hang (Laotian), Pa fa hang (Laotian), Pa fa lai (Laotian)  240 cm WD male/unsexed  Known from the Mekong basin (Ref. 27732). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Reported also to occur in the Mekong above the great waterfalls (Ref. 9497). Also Ref. 12693, 30857. 
Gastromyzontidae Vanmanenia crassicauda Kottelat, 2000 Fr native   6.70 cm SL male/unsexed  Known only from Nam Xam and Nam Ma basins in Laos (Ref. 36949). Also Ref. 43281, 44416.  No picture yet.
Gastromyzontidae Vanmanenia orcucampus Kottelat, 2017 Fr native    Type locality of Vanmanenia orcucampus, Nam Ngum at Ban Khangviang, Xiangkhouang Province (Ref. 124503). Also Ref. 120400.  No picture yet.
Gastromyzontidae Vanmanenia serrilineata Kottelat, 2000 Fr native   6.49 cm SL male/unsexed  Known from Nam Ou and Nam Tha basins of the Mekong in northern Laos (Ref. 36949). Also Ref. 43281, 95066.  No picture yet.
Siluridae Wallago attu (Bloch & Schneider, 1801) Fr, Br, Fi native  Khao (Laotian), Pa khao (Laotian)  240 cm TL male/unsexed  Known from Mekong River system (Ref. 9497). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Collected from Tha Ngon, Tha Bo and Sithan Tay of the Mekong basin (Ref. 4792). Its numbers have declined in the Khone Falls (Ref. 37772). Also Ref. 30857, 37770, 37772, 43281, 56905. 
Siluridae Wallago micropogon Ng, 2004 Fr native  Pa koon (Laotian), Pa khoun (Laotian)  154 cm SL male/unsexed  Found in the Mekong basin (Ref. 43281). Stays near the edge of the forest during the period of low water and enters the flooded forest during high water. Caught during high waters when it enters the flooded forest mainly with "jun" (trap-door traps) and also by single hooks (bet ken) baited with pa soi (Ref. 9497). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Its numbers have declined in the Khone Falls (Ref. 37772). Reported to migrate downstream in October-November (Ref. 37770). Fish migrate in groups into smaller streams to spawn (Ref. 37770). Also Ref. 30857, 37772, 56905. 
Belonidae Xenentodon cancila (Hamilton, 1822) Fr native  Pa kathong (Laotian), Pa katong (Laotian)  40.00 cm TL male/unsexed  Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Occurrence in southern Laos is uncertain (Ref. 9497). Also Ref. 50526. 
Belonidae Xenentodon canciloides (Bleeker, 1854) Fr native  Pa sa thong (Laotian)  30.00 cm SL male/unsexed  Known from the Mekong basin (Ref. 43281). Also Ref. 4792. 
Botiidae Yasuhikotakia caudipunctata (Taki & Doi, 1995) Fr native  Pa mou man (Laotian)  9.00 cm SL male/unsexed  Known from the Mekong basin (Ref. 43281). Occurs in the middle Xe Bangfai, a tributary of the Mekong basin (Ref. 27732). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Museum: Mekong River at Hatsalao, near Pakse, NSMT-P 35935 (holotype, 8.2 cm SL) (Ref. 13469); Mekong, BMNH 1995.4.24.1-5 (Sithan Tay,near Vietiane, Laos, 9 April 1971 (Ref. 31982). Also Ref. 30857, 33021. 
Botiidae Yasuhikotakia eos (Taki, 1972) Fr native  Pa mou man (Laotian), Pba moo mun (Laotian)  11.00 cm TL male/unsexed  Known from the Mekong basin in the middle Xe Bangfai (Ref. 27732). Found in Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Museum: Mekongriver at Ban Hang Khone, just below Khone falls, CAS 96991 (Ref. 5515). Also Ref. 4792, 30857. 
Botiidae Yasuhikotakia lecontei (Fowler, 1937) Fr native  Pa mou man (Laotian)  15.00 cm SL male/unsexed  Occurs in middle Xe Bangfai, a tributary of the Mekong basin (Ref. 27732). Found in the Mekong mainstream at Hat Village, Muang Khong District (Ref. 37769) and Ban Hang Khone, a village on an island in the middle of the mainstream Mekong River just below the Great Khone Waterfalls in Khong District, Champasak Province (Ref. 37767). Also Ref. 4792, 13469, 30857, 37841. 
Botiidae Yasuhikotakia longidorsalis (Taki & Doi, 1995) Fr native   8.00 cm SL male/unsexed  Found in the Mekong River near Pakse and the Nam Khon River, a tributary connected to the Mekong River via the Nam Ngum River at Tha Ngon (Ref. 13469). Also Ref. 30857, 33021, 26580, 43281. 
Botiidae Yasuhikotakia modesta (Bleeker, 1864) Fr, Fi native  Keeo gai (Laotian), Pa moo (Laotian), Pa mou man (Laotian), Pa mou mang (Laotian), Pba moo mun (Laotian) occasional (usually not seen) 25.00 cm SL male/unsexed  Occurs in the lower Xe Bangfai, a tributary of the Mekong basin (Ref. 9497, 27732). Largest of 8 species of Botia occurring in Laos. Migrates upstream in large numbers with Cirrhinus spp. during Chinese New Year in January.-February (Ref. 9497). Also reported to migrate upstream during the dry season in December/February in Southern Laos (Ref. 37769). Ban Hang Khone fishers never see it with eggs (Ref. 9497). Juveniles around 2 cm appear from March to May at Xayaboury (Ref. 37770). One of the most important species in the specilized "tone" trap fishery at Ban Hang Khone, immediately downstream the Khone Falls between January to March (Ref. 37770). Museum: Mekong R. at Hatsalao, near Pakse, IBRP 5610 (Ref. 13469). Museum: Mekong river, CAS 93257, 94875 (Ban Hang Khone, just below Khone falls) (Ref. 5515). Also Ref. 30857, 36654, 37767. 
Botiidae Yasuhikotakia morleti (Tirant, 1885) Fr native   10.00 cm TL male/unsexed  Found in the Mekong basin (Ref. 43281). Also Ref. 4792, 30857 (listed as Botia cf. morleti). 
Botiidae Yasuhikotakia splendida (Roberts, 1995) Fr native   10.00 cm SL male/unsexed  Known from the Se Kong watershed of the Mekong basin (Ref. 31466). The Se Pa Waterfall, 20 m high and one kilometer upstream from the collection site of the holotype ( Xe Pian 5-6 km upstream from Ban Hin Lat, 1 km downstream from Se Pa Waterfall, Attapeu), probably represents the upper limit of distribution of this species in the Xe Pian. Also Ref. 43281. 
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