Siamese fighting fish

The Siamese fighting fish (Betta splendens), commonly known as the Siamese fighter, or locally as the betta, is a freshwater fish native to Mainland Southeast Asia, namely Cambodia, Laos, Myanmar, Malaysia, Thailand, and Vietnam. It is one of more than 70 species of the genus Betta, but the only one eponymously called "betta", owing to its global popularity as a pet; Betta splendens are among the most popular aquarium fish in the world, due to their diverse and colorful morphology and relatively low maintenance. Betta fish are endemic to the central plain of Thailand, where they were first domesticated more than 1,000 years ago, among the earliest of any fish. They were initially bred for aggression and subject to gambling matches akin to cockfighting. Bettas became known outside Thailand through King Rama III (1788–1851), who is said to have given some to Theodore Cantor, a Danish physician, zoologist, and botanist. They first appeared in the West in the late 19th century, and within decades became popular as ornamental fish. B. splendens's long history of selective breeding has produced a wide variety of coloration and finnage, earning it the moniker "designer fish of the aquatic world". Bettas are well known for being highly territorial, with males frequently engaging in aggressive interactions when kept together; without a means of escape, this usually results in the death of one or both fish. Female bettas can also become territorial toward one another in confined spaces. Bettas are exceptionally tolerant of low oxygen levels and poor water quality, owing to their special labyrinth organ, a characteristic unique to the suborder Anabantoidei that allows for the intake of surface air. In addition to its worldwide popularity, the Siamese fighting fish is the national aquatic animal of Thailand, which remains the primary breeder and exporter of bettas...