"Betta Fish" The Siamese fighting fish (Betta splendens), commonly known as the betta,[2] is a freshwater fish native to Southeast Asia, namely Cambodia, Laos, Myanmar, Malaysia, Indonesia, Thailand, and Vietnam.[3][4] While one of 73 species of the genus Betta, only Betta splendens are eponymously called "bettas", due largely to their global popularity as pets: they are among the most widely available aquarium fish in the world, due to their varied and vibrant colour, diverse morphology, and re