Arapaima is a large Amazonian fish famous for breathing air and surviving in oxygen-poor floodplain waters.
Arapaima are among the world’s largest freshwater fish, with historical reports of individuals reaching several metres in length. They possess a modified, highly vascularized swim bladder that functions like a lung, allowing them to gulp atmospheric air at the water’s surface.
This adaptation is valuable in Amazon floodplain lakes and channels where warm, stagnant water can contain little dissolved oxygen. Arapaima must surface regularly, which also makes them vulnerable to fishers who can detect their breathing rhythm.
The name pirarucu is widely used for arapaima in Brazil, while paiche is common in Peru and other Spanish-speaking areas. These names can make the fish seem like different species, but they commonly refer to arapaima, especially Arapaima gigas.