Arapaima

The arapaima, pirarucu, or paiche (Arapaima gigas) is a South American tropical freshwater fish. It is one of the largest freshwater fish in the world, reportedly with a maximum length in excess of 3 m (9.8 ft.) and weight up to 200 kg (440 lb.). As one of the most sought after food fish species in South America, it is often captured primarily by handheld nets for export, by spearfishing for local consumption, and, consequently, large arapaima of more than 2 m are seldom found in the wild today.
The diet of the arapaima consists of fish or even other kinds of small animals, including birds. The fish also has the ability to breathe air from the surface due to a lung-like lining of its throat, an advantage in oxygen-deprived water that is often found in the Amazon River. This fish is therefore able to survive extensive drought periods by gulping air and burrowing in the mud or sand of the swamps.
The arapaima has also been introduced for fishing in Thailand and Malaysia. It is also considered an aquarium fish, although it obviously requires a large tank and ample resources.
Fossils of arapaima or a very similar species have been found in the Miocene Villavieja Formation of Colombia. [1]
The tongue of this fish is thought to have medicinal qualities in South America. It is dried and combined with guarana bark, which is grated and mixed into water. Doses of this are given to kill intestinal worms

Reproduction
Due to the geographic range that arapaima inhabits, the animal's life cycle is greatly affected by the seasonal flooding that occurs. Half of the year the arapaima experiences an abundance of water, which is a benefit to these aquatic organisms; however, the other half of the year the arapaima experiences drought conditions. The arapaima has adapted to this great fluctuation in many aspects of its life, including reproduction. The arapaima lays its eggs during the months of February, March, and April when the water levels are low. They build a nest approximately 50 cm wide and 15 cm deep, usually in sandy bottomed areas. As the water rises the eggs hatch and the offspring have the flood season to prosper, during the months of May to August. Therefore, the yearly spawning is regulated seasonally. The arapaima is a mouthbrooder.

Economic Importance for Humans
The arapaima is hunted and utilized in many ways by local human populations. Arapaima are harpooned or caught in large nets and the meat is said to be delicious. Since the arapaima needs to swim up to breathe air, traditional arapaima fishers often catch them by first clubbing them and then harpooning them dead. One individual can yield as much as 70 kg of meat. In addition, the arapaima's bony tongue is often used to scrape cylinders of dried guarana, an ingredient in some beverages, and the bony scales are used as nail files. This animal also appears in the pet trade, although to keep an arapaima correctly requires a large tank and can prove quite difficult.

http://en.wikipedia.org/wiki/Arapaima