Arapaima is the freshwater fish genus that includes the giant South American fish Arapaima gigas.
Arapaima are enormous air-breathing fishes native to the Amazon and Essequibo basins. Their bodies are covered by large scales, and they regularly rise to the surface to gulp air because their modified swim bladder functions as a lung.
Arapaima gigas was historically treated as the main species in the genus, but modern research has described additional species. This makes older sources that call every arapaima A. gigas less precise than current taxonomic treatments.
The fish is also known as pirarucu in parts of Brazil and paiche in Peru. Those names refer to arapaima fish rather than separate genera. Fishing pressure and habitat changes have made conservation important in parts of their range.