ArapaimaArapaima gigasWhere and when to see them

The arapaima is one of the world's largest freshwater fishes and an iconic inhabitant of the Amazon basin. Known in Brazil as pirarucu, it has a long, heavily scaled body and must surface regularly to breathe air. It is an important food fish and has long-standing cultural and economic significance for Amazonian communities. Heavy fishing has depleted populations in many areas, while community-based management has helped some populations recover. Several species of Arapaima are recognized, so not every arapaima seen in the Amazon can confidently be identified as Arapaima gigas.

Size

Commonly reaches about 2 m in length; exceptionally large individuals can approach 3 m.

Weight

Large adults can weigh over 100 kg, with exceptional individuals reaching around 200 kg.

Lifespan

Often reported as around 15 to 20 years, although longevity in the wild is not well documented.

Status

Data Deficient (IUCN).

Arapaimas spend much of their time in slow-moving water, periodically rising to gulp air at the surface. Their modified swim bladder functions as an air-breathing organ, allowing them to occupy waters with little dissolved oxygen. Surfacing can produce a distinctive gulping sound and a brief view of the head or back. Their movements follow the flood cycle, with fish entering newly flooded habitats as water levels rise. As waters fall, they become concentrated in remaining lakes and channels. Breeding is linked to seasonal water-level changes, and pairs prepare a shallow nest in the bottom substrate. Parents guard the nesting area, and the male closely attends the young as they move together near the surface.

• Arapaimas must breathe atmospheric air, even when their water contains oxygen.
• Their scales combine a hard outer layer with a tough, flexible inner structure.
• Males closely guard schools of young fish.
• Trained observers use surfacing breaths to help count arapaimas in managed lakes.

Wildlife opportunities depend on the river reach, water levels and species. River-specific viewing months have not been confirmed; general species seasons are not a local sighting forecast.

Arapaima gigas is native to the Amazon basin, where it is associated mainly with warm, lowland freshwater habitats. It inhabits floodplain lakes, backwaters, and slow-flowing channels connected to the river system. During high water, arapaimas can move into flooded forest and other inundated floodplain habitats. Their ability to breathe air helps them survive in oxygen-poor water, but they still require access to the surface. Seasonal connections between lakes, channels, and flooded areas are important for movement, feeding, and reproduction.

Arapaimas feed mainly on fish, capturing prey with a rapid opening of the mouth that draws water and food inward. They also consume crustaceans and other animal prey when available. Young fish eat smaller prey, including aquatic invertebrates, before taking larger fish as they grow. Feeding opportunities change as seasonal flooding alters access to prey and habitat.

Common name

Arapaima

Scientific name

Arapaima gigas

Animal group

Fish

Size

Commonly reaches about 2 m in length; exceptionally large individuals can approach 3 m.

Weight

Large adults can weigh over 100 kg, with exceptional individuals reaching around 200 kg.

Lifespan

Often reported as around 15 to 20 years, although longevity in the wild is not well documented.

Status

Data Deficient (IUCN).

Identification

Look for a very large, elongated fish with a broad, flattened head and large, mosaic-like scales. Adults are generally gray to olive, often with reddish markings toward the rear of the body and tail. The dorsal and anal fins sit far back near the rounded tail, rather than midway along the body. A brief surface view may identify an arapaima, but distinguishing Arapaima gigas from related species usually requires close examination.