Catfish are a very diverse group of
fish. Most are found in freshwater environments of all kinds, but there are also a couple of Atlantic Ocean species. They range in size and behavior from well over a hundred pound fish eaters, to detritivores (species that eat dead material on the bottom), even to a tiny parasitic species commonly called the
candiru (
Vandellia cirrhosa).
They belong to a superorder called the Ostariophysi, which also includes the Cypriniformes, Characiformes, and Gymnotiformes. Catfish have no scales (and are therefore not kosher).
