The scientific name of the Siamese fighting fish is Betta splendens.
Betta splendens is a small freshwater fish native to Thailand, Cambodia, Laos, and Vietnam. It is famous for the aggressive behavior of males toward one another and for its elaborate selectively bred colors and flowing fins in the aquarium trade.
Wild Siamese fighting fish are generally less dramatically finned than many domestic varieties. They inhabit shallow, slow-moving waters such as rice paddies, floodplains, canals, and marshes. Like other members of the labyrinth-fish group, they can breathe atmospheric air using a labyrinth organ.
The common name can cause confusion because “betta” is also used for many other species in the genus Betta. Betta splendens specifically refers to the species traditionally known as the Siamese fighting fish.