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.