Description: The Arapaima is also known as Paiche and Pirarucu. It is one of the largest freshwater fishes in the world. The head is depressed and has a wide mouth, with the prominent lower jaw having no barbels. It is streamlined with two small pectoral fins on the sides of the body close to the front; dorsal and anal fins are so far back that they appear to be part of the tail. The coloration of the body is largely gray to green, with fins and scales on the back half of the body sometimes being edged in red and orange specks on the body. The underside is white to yellow. Species in the order Osteoglossiformes have a bony or toothed tongue.
Size: Arapaimas have been reported to reach 15 feet (4.5 m) in length, however, currently there are few, if any, this size. They are still found at average lengths of more than 6.6 feet (2 m) and weights of up to 440 pounds (200 kg). In captivity they will often reach an average length of five feet (1.5 m).
Behavior: Even though the gills of Arapaimas can remove oxygen from the water, they have a swim bladder made up of lung-like tissue, which enables them to extract oxygen from the air. To do this, they must surface every 10-20 minutes to breathe air, making a loud, distinctive gulp, which makes them easy targets for fishermen with harpoons (commonly eaten in their native range). They are very aggressive, even toward species of their own kind. If not on the move, they may be seen resting on the bottom among plants or drifting near the surface.
Diet: These predatory fish mainly feed on crustaceans and other fish. They are capable of leaping out of the water to grab birds, reptiles or small mammals from low- hanging branches.
Communication: Communication by adults to their offspring is by releasing a special chemical substance (pheromone) from the head. This keeps the larvae close to the adults so they can help protect them from predators.
Reproduction: Arapaimas build a nest that is about 20 inches (51 cm) in diameter and six inches (15.2) deep, in a sandy area. After the eggs are laid by the female, they are fertilized by the male. The eggs and fry are guarded by both parents. The nests are built during the low water period, then when the waters start to rise, the eggs hatch and there is abundant food for the young.
Habitat/range: Native to the Amazon River Basin in South America, the Arapaima gigas has been introduced and established outside its native range. Their habitat varies with the seasons; river channels and lakes are selected during dry season for egg laying and move into flooded forest areas during the rainy season.
Status: Due to their high value as a food source (50% of body weight is edible, boneless meat) and the ease in locating these vulnerable fish (surface air-gulping) they have been over-fished. They are listed as Data Deficient (DD) on the IUCN Red List and CITES, Appendix II.