Glass catfish, Ghost catfish, Phantom catfish
Kryptopterus vitreolus, known in the aquarium trade traditionally as the glass catfish and also as the ghost catfish or phantom catfish, is a small species of Asian glass catfish. It is commonly seen in the freshwater aquarium trade, but its taxonomy is confusing and was only fully resolved in 2013. It is endemic to Thailand, and found in rivers south of the Isthmus of Kra that drain into the Gulf of Thailand and river basins in the Cardamom Mountains. There are also unconfirmed reports from Penang in Malaysia.
Until 1989, it was considered to be the same as the "glass catfish" Kryptopterus bicirrhis, a larger species infrequently seen in the aquarium trade. Subsequently, the ghost catfish commonly seen in the aquarium trade was believed to be the same as K. minor, but in 2013 it was established that the aquarium specimens actually represented another species, which was described as K. vitreolus. The true K. minor, which is restricted to Borneo, has rarely (if ever) entered the aquarium trade.
This is a transparent freshwater catfish with two long barbels. Standard lengths may range up to 8 cm (3.1 in), but usually only reach around 6.5 cm (2.6 in) 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. During strong illness and 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.
The aquarium trade in K. vitreolus generally relies on wild-caught specimens, and there are concerns that this may be unsustainable due to the volume and its limited range. Unlike many other aquarium fish, it is not known to be bred at commercial facilities.
