The wild ancestors of this fish are native to the rice paddies of Thailand, Laos, Cambodia, and Vietnam and are called pla-kad (lit. biting fish) in Thai or trey krem in Khmer.
The people of Siam and Malaya (now Thailand and Malaysia) are known to have collected these fish prior to the 19th century.
In the wild, bettas spar for only a few minutes or so before one fish backs off. Bred specifically for fighting, domesticated betta matches can go on for much longer, with winners determined by a willingness to continue fighting. Once one fish retreats, the match is over.