- a large freshwater fish, Arapaima gigas, of Brazil and Guiana, reputed to reach a length of 15 feet (4.5 meters) and a weight of 500 pounds (225 kilograms).
- a very large primitive freshwater teleost fish, Arapaima gigas, that occurs in tropical South America and can attain a length of 4.5 m (15 ft) and a weight of 200 kg (440 lbs): family Osteoglossidae
