Arapaima

Presentation

The Arapaima (Arapaima gigas) is one of the largest freshwater fish in the world, native to the Amazon basin. This fish has an elongated body covered with large, rigid scales, often tinged red towards the tail. A formidable predator, it hunts other fish and supplements its respiration thanks to a primitive lung allowing it to breathe atmospheric air. Its impressive size and appreciated flesh make it a highly sought-after species by local and international fishing. It is today threatened by overfishing in certain regions of its range.

The Arapaima has a massive, elongated body, covered in thick, tough scales that protect it from piranha attacks. Its head is flat and its wide mouth allows it to suck in its prey. It has a swim bladder modified into a respiratory organ, which requires it to regularly rise to the surface to breathe.

Characteristics

Indicative values: they vary by subspecies, sex and region.

Habitat and distribution

Arapaima lives in slow-moving rivers, lakes and flooded areas of the Amazon basin. It particularly likes stagnant or poorly oxygenated waters, where its air breathing gives it an advantage over other fish. It is also found in swampy areas and floodplains during flood season.

Behaviour

This fish is rather solitary outside of breeding periods. It must rise to the surface regularly, approximately every 10 to 20 minutes, to breathe atmospheric air using its primitive lung. It is active mainly in calm, poorly oxygenated waters, where this respiratory adaptation gives it a clear advantage.

Reproduction

Reproduction generally takes place in the low water season. Both parents help protect the nest and fry, a rare behavior among fish. The male secretes a substance on his forehead which attracts and guides the young around him for several weeks.

Peculiarities

The Arapaima breathes atmospheric air using a vascularized swim bladder that functions like a lung. Its very hard scales have inspired research in materials science for their resistance to punctures. It is among the largest freshwater fish in the world.

Threats and conservation

Overfishing poses the main threat to the species in many regions of its range. The degradation and fragmentation of its aquatic habitat linked to deforestation and dams also aggravate its local decline. Management and supervised fishing programs now exist in certain protected areas of Brazil.

References

Profile updated 30 August 2026 · Reviewed by the TunisieVet editorial team.