The Amazon basin contains the largest number of freshwater fish species in the world -- more than 2,500 species.
Phractocephalus hemioliopterus, is a pimelodid (long-whiskered) catfish named for its red or orange caudal fin. In
Arapaima gigas, Pirarucu, or paiche is a South American tropical freshwater fish. It is a living fossil and one of the largest freshwater fishes in the world. Arapaima can reach lengths of more than 2 m (6.6 ft), in some exceptional cases even more than 2.5 m (8.2 ft). The maximum-cited weight for the species is 200 kg (440 lbs). As one of the most sought after food fish species in South America, it is often captured primarily by handheld nets for export, by spear fishing for local consumption, and, consequently, large arapaima of more than 2 m are seldom found in the wild today. The diet of the arapaima consists of fish, crustaceans, and other small animals. The fish is an air-breather, using its labyrinth organ, which is rich in blood vessels and opens into the fish`s mouth an advantage in oxygen-deprived water that is often found in the
Colossoma macropomum is a freshwater fish of the subfamily Serrasalminae, family Characidae. It is also known by the names Pacu, Black pacu, Black-finned pacu, Giant pacu, Cachama and Gamitana. Fossils of a living species of Colossoma from the Miocene have been described, suggesting a very conservative history for a specialized herbivorous fish. The tambaqui is the largest characin of