Glass Catfish

About

The glass catfish (Kryptopterus bicirrhis) comes with an important caveat for anyone who has kept what they thought was this species before: much of the aquarium trade has historically sold a close relative, K. vitreolus, under this name. The real K. bicirrhis is actually not transparent in life, which is the quickest way to tell them apart. It is a mid-sized catfish native to large river systems across Southeast Asia, including the Mekong and Chao Phraya basins, the Malay Peninsula, Sumatra, and Borneo, where it schools in fast-moving, often turbid water along river margins and seasonally enters flooded fields. In the wild, groups of up to a hundred individuals are not unusual, and that schooling instinct carries directly into aquarium keeping. A lone specimen or a small group of two or three will be visibly stressed and unlikely to thrive. Aim for ten or more if space allows, with a minimum of around six as a practical lower limit. The species is peaceful toward similarly sized tankmates but can pick off very small fish, and it does not hold its own well against boisterous or aggressive species. Peaceful cyprinids, loaches, and other catfishes tend to work well as companions. This is an intermediate-level fish, not because it is fragile, but because meeting its schooling and social requirements takes planning.