Order : Cypriniformes
Family : CYPRINIDAE
Species : Danio albolineatus
Maximum Length : up to 6.5 cm

In its native range Danio albolineatus (Pearl Danio) inhabits shallow, fast-flowing hill streams, and is active in in the surface layer. Its diet comprises insects which have fallen into such streams, as well as in-situ aquatic fauna (Ref: Fishbase).

In the field, this small cyprinid appears plain or yellowish/pinkish in colour, with no easily identifiable markings or patterning. Close inspection of field photographs may reveal faint bluish and orange stripes extending from below the dorsal fin to the base of the tail fin, and a faint, incomplete lateral line.

This species occurs naturally in Myanmar, Thailand, Laos, and the Indonesian island of Sumatra. It is a popular aquarium species and as a consequence has been introduced to other territories, including Singapore where there are records from the Mandai, Bukit Brown, Bukit Timah and Tengah areas (Tan et al, 2020; Tan et al, 2013).

Figs 1 and 2 : Examples from Bukit Brown, Singapore where this species thrives (along with Danio rerio) in neglected, modified streams; the natural sandy substrate was replaced by concrete in the 1920's when the area was first used as a cemetery.

Fig 3 : Ppen-country stream at Bukit Brown; the introduced Pearl Danio thrives in this modified habitat.

Fig 4 : A pair of Pearl Danio (left) with a lone Indochinese Spotted Barb (right).


References :

Tan Heok Hui, Kelvin Lim Kok Peng, Liew Jia Huan, Low Bi Wei, Rayson Lim Bock Hing, Jeffrey Kwik Teik Beng & Darren C.  J. Yeo. (2020). The non-native freshwater fishes of Singapore: an annotated compilation. Raffles Bulletin Of Zoology, 68: 150-195.

Jonathan Y. H. Tan, Lowell H. C. Tan, Glenn Quek, Valerie S. F. Lim and Tan Heok Hui.  (2013). The fish fauna of Bukit Brown, Singapore. Nature in Singapore, 6: 229-237.

Links : 

Fishbase

Thanks to Tan Heok Hui for helping with identification.