Which fish species is commonly called the redtail catfish?

Phractocephalus hemioliopterus is the fish species commonly called the redtail catfish.

This large pimelodid catfish is native to the Amazon, Orinoco, and Essequibo river basins of South America. Its dark body, pale underside, and vivid red-orange tail make it popular in the aquarium trade, where young specimens can look deceptively manageable.

Adult redtail catfish can become very large, so public aquariums and specialist facilities rather than ordinary home tanks are usually more suitable for them. They are opportunistic predators that eat fish, crustaceans, and other animals they can swallow.

The red tail is the key feature behind the common name, but it is not the only South American catfish with striking coloration. It is also sometimes confused with hybrid aquarium catfish sold under trade names. The scientific name Phractocephalus hemioliopterus refers to the recognized species itself.