Redtail catfish
(Phractocephalus hemioliopterus)

The redtail catfish, Phractocephalus hemioliopterus, is a pimelodid (long-whiskered) catfish. In Venezuela, it is known as cajaro, and in Brazil, it is known as pirarara, stemming from the Tupi language words pirá and arara.

It is the only extant species of the genus Phractocephalus.

This fish is common in the aquarium trade, although its massive adult size makes it unsuitable for all but the largest aquariums.

They feed on fish, crustaceans and fallen fruits.

Phractocephalus hemioliopterus can reach about 1.8 m (5 ft 11 in) in length, and about 80 kg (180 lb) in weight. However, this is exceptionally rare, and most do not approach this size. They average 3 ft 6 in–4 ft 6 in; 1.1–1.4 m in length.

These colorful large catfishes have a brownish back, with yellow sides, and characteristic orange-red dorsal fin and caudal fin (hence the common name). Sometimes the dorsal, pelvic and anal fins are also red.

They have a broad head with long whiskers, dark black body and white underneath that extends from the mouth to the caudal fin. It has a pair of barbels on the upper jaw, and two pairs on the lower jaw. Their whiskers are sensitive and have chemical reception cells which are used as the sense of smell. They breed using external fertilization after laying their eggs. They communicate by making a clicking sound to warn off potential dangers.

Distribution and habitat
The redtail catfish is native to the Amazon, Orinoco, and Essequibo river basins of South America, in Ecuador, Venezuela, Guyana, Colombia, Peru, Suriname, Bolivia, and Brazil. It is found only in fresh water, and inhabits larger rivers, streams, and lakes.

They eat during the evening and night and stay motionless during the day. They are bottom-dwellers and move about quite slowly. Red-tailed catfish are territorial fish.