The arapaima is often called the world’s largest freshwater scaled fish.
Arapaima are enormous air-breathing fish native to the Amazon and Essequibo basins of South America. They can exceed 2 metres in length, although very large individuals are now less common in many areas because of fishing pressure. Their bodies are protected by large, strong scales.
Arapaima must surface regularly to gulp air because their modified swim bladder functions partly like a lung. This adaptation helps them survive in warm, oxygen-poor floodplain waters. They prey on fish, crustaceans and other animals, and can catch prey near the water’s surface.
“Pirarucu” is a common Brazilian name for arapaima, not a separate species in ordinary usage. Scientists recognize several species in the genus Arapaima, so the name can refer to the genus as a whole rather than only one species.