The arapaima is one of the world’s largest freshwater fish.
Arapaima are enormous air-breathing fish found in the Amazon and Essequibo basins of South America. In Brazil, the fish is also widely known as pirarucu. Historical reports describe individuals exceeding 3 metres in length, although such giants are now uncommon because of fishing pressure.
Unlike most fish, arapaima must regularly gulp air at the surface. Their modified swim bladder functions like a lung and allows them to survive in warm, oxygen-poor floodplain waters. They rise to breathe roughly every 10 to 20 minutes, making them conspicuous to fishers.
The genus includes several recognised species, and modern research has revised older assumptions that all arapaima belonged to one species. The fish is important both culturally and economically, while community-managed fisheries have helped some populations recover.