Catfish
The catfish have a snakelike body that is laterally compressed and flattened ventrally (belly). A pair of short barbels is on the upper jaw; two pairs of long, feeler-like barbels are near the mouth on the lower jaw. The dorsal and pectoral fins have soft rays and spines; the pelvic fins are thoracic (located on or near the chest), without spines; and there is no adipose fin. The anal fin has three to 16 soft rays.
The body is naked (scaleless); some species, however, may be covered with hard plates. Catfishes are gray, brown, greenish, or yellowish above and lighter below. Most have round black spots on the sides; in some species, the spots are blue or silvery.
The catfish is a scavenger that eats worms, snails, insects, insect larvae, small fishes, salamanders, frogs, snakes, bird eggs, dead organisms or organisms still alive, and plant matter. Some species are not scavengers but may prey on large fish; holes have been found in largemouth bass (Micropterus) stomachs containing smaller fishes.
The black bullhead (Ameiurus melas), the only North American representative of the family Ictaluridae, is a common North American catfish. It reaches a maximum length (total length) of 35 cm (14 inches). The black bullhead is found in quiet waters of lakes, ponds, and sluggish streams. Other members of the family are much larger; the South American genus Brachyplatystoma may reach a length of 2.5 m (8 feet). The South American family Pimelodidae is represented by the 1-m-long (3.3-ft) onechus, which lives in rivers and lakes of tropical South America.
Modern catfishes belong to the suborder Siluroidea, which probably evolved in the Cretaceous Period (145.5 million to 65.5 million years ago). The suborder includes about 800 species, ranging from 5 cm (2 inches) to 2.75 m (9 feet). They are found in all seas and in most freshwater habitats; however, they are very abundant only in the rivers of southeast Asia. One species, Parasilurus asotus, is native to the fresh waters of India, Ceylon (Sri Lanka), Malaysia, Indonesia (Java), Sumatra, Borneo, Philippines (Mindanao), and New Guinea.