The Siamese fighting fish (Betta splendens), also known as the "beta fish" or just "betta", is one of the most popular species of freshwater aquarium fish. It is native to the rice paddies of Thailand and Cambodia and called pla-kad or trey krem("Fighting Fish") in its native [Khmer/Thai].
The Betta fish is a relatively inexpensive way to enter the aquatic species ownership realm. Because these fish are descendants of the wild betta fish which live in oxygen-poor environments, Siamese fighting fish are capable of living in smaller containers than most aquarium fish, without the filters and aerators that other aquarium fish require, although this isn't the ideal living situation. The name Betta (or betta) is pronounced. The name Betta is not to be confused with the Greek letter beta. Instead, the name of the genus is derived from ikan bettah, taken from a local dialect of Thailand.
Betta splendens usually grow to an overall length of about 6.0 centimetres (2.4 in), though some varieties reach 8.0 centimetres (3.1 in) in length. In recent years breeders have been able to create "Giant Bettas" that exceed 8.0 centimetres (3.1 in) due to the manipulation of a mutant gene. Although bettas are known for their brilliant colors and large, flowing fins, the natural coloration of B. splendens is a dull green and brown, and the fins of wild specimens are relatively short. However, brilliantly colored and longer finned varieties (i.e. Veiltail; Delta; Superdelta; and Halfmoon) have been developed through selective breeding.