Glass catfish

Appearance

This is a transparent freshwater catfish with two long barbels. Standard lengths may range up to 8 cm , but usually only reach around 6.5 cm in total length. They are transparent because, like all catfish, they are scaleless, and catfish within the genus ''Kryptopterus'' lack body pigment. Most of their organs are located near the head; with a magnifying glass, their heart can be seen beating. When the light strikes the fish just right, it can create an iridescent rainbow color. After death, they turn milky white. The scientific species name ''vitreolus'' is derived from the Latin ''vitreus'', which means glass. Among described species of ''Kryptopterus'', only two other species, ''K. minor'' and ''K. piperatus'', have clearly transparent bodies and both these are largely–if not entirely–absent from the aquarium trade. The body of others, including ''K. bicirrhis'', are only somewhat translucent or opaque.

Habitat

Native to rivers in Thailand, these catfish prefer tanks with open swimming areas with a moderate current, and planted areas to provide shelter. Timid and non-aggressive fish, they should always be kept as a group of at least five, and can be kept with other fish species of similar size and temperament. Ghost catfish are highly sensitive to changes in water quality and pH. The pH should be slightly acidic , water hardness should be low and the water temperature should be around 25 °C . These fish have a reputation for being finicky eaters; they prefer live food such as mosquito larvae, bloodworms and brine shrimp , but can be weaned to flake food with time.

''Kryptopterus'' species are different from most other catfish because they are free-swimming and live in the mid- to upper region of the water. Ghost catfish commonly favor dark places to being out in the open light. A small school of them may hide under elevated rocks, logs, or the shadow of plants. Sometimes, however, one or two may venture out into the open and swim in the upper level of the water. They can be enticed to do this more often if the flow of water in the tank is arranged so that their favorite hiding spots are sheltered, while a gentle current flows in the open areas. Thus, they will move in the open especially at feeding time, as they like to go after food drifting in the current. A generous growth of aquatic plants is necessary for their well-being, and swimming plants can filter out overly bright light, which they seem to find unpleasant.

Breeding has reputedly been achieved in the aquarium, but is not documented. As it seems, they are bred in numbers in outdoor ponds in Southeast Asia for trade, but details are unknown.

Uses

This catfish is a major ingredient of some of the salty fish sauces used in Asian cooking.