Long whiskers catfish

About

Found along the coastlines and river systems of the eastern Indian Ocean rim, from India through Indonesia and Vietnam, this medium-to-large catfish, Mystus gulio, is one of those species that blurs the line between freshwater and brackish. It is primarily a brackish water fish by nature, but moves freely into freshwater habitats, where adults tend to favor larger rivers and streams with muddy or clay bottoms rather than smaller tributaries. One of its more unusual traits is facultative air breathing. It can gulp air when dissolved oxygen is low, an adaptation well suited to the murky estuarine environments it calls home. In the wild it forms active schools of ten to twenty-five individuals and is a diurnal swimmer, so you actually get to see it during the day rather than hiding in a cave until lights-out. That schooling behavior means keeping a group is strongly preferred over a lone specimen, and given the adult size, these fish can push well past a foot in length, a spacious setup is genuinely necessary. Its carnivorous diet and eventual size place it firmly in intermediate keeper territory. If you have the room and can accommodate its preference for slightly hard, mildly acidic to neutral water, it rewards you with active, social behavior that smaller catfish simply cannot match.