The tail may be squared or deeply forked, depending on the particular kind of catfish. None of the catfishes have scales. Members of the catfish family in the U. S. were originally distributed in most states east of the Rocky Mountains, but various species have been widely introduced into western states where they did not occur naturally. Mature individuals among the species range in size from several pounds for the channel catfish to only a few ounces for the tiny madtoms. Large catfish are good food fish, and the madtoms and stonecat are good bass bait.
Catfishes are generally warmwater fish.
They frequently inhabit mud-bottomed streams, ponds, and lakes, although channel catfish and madtoms prefer swift, cool streams. Catfishes can withstand water with low oxygen levels and considerable pollution. The sensory barbels are used to locate food at night. The male usually excavates a saucer-shaped depression for a nest. Channel catfish dig tunnels in streambanks or under logs for their nests.