Pirarucu, or Arapaima, an important food fish of South America. It is one of the largest freshwater fish in the world, thought to be exceeded in size only by the European catfish. The pirarucu averages about 7 feet (2 m) in length and 175 pounds (80 kg) in weight, but may grow to more than twice that length and weight. Its body is green at the fore part, shading into red at the tail.

The pirarucu is Arapaima gigas of the family Osteoglossidae.