Arapaima is often described as the world’s largest scaled freshwater fish.
Arapaima are enormous air-breathing fish native to the Amazon Basin. The genus contains several species, including Arapaima gigas, and some individuals can exceed 3 metres in length. Their large scales, broad bodies and upturned mouths make them distinctive among South American river fish.
Arapaima must surface regularly because they breathe atmospheric air using a modified, highly vascularised swim bladder. This adaptation helps them live in warm, oxygen-poor floodplain waters. They are also important food fish and have been affected by commercial fishing, although managed fisheries have helped some populations recover.
The name is sometimes confused with “pirarucu,” a major common name used in Brazil. “Arapaima” refers to the fish and its genus, while “pirarucu” is especially common in Portuguese-speaking Amazonian regions.