Anabantiformes

Anabantiformes is an order of freshwater bony fish. They are collectively known as labyrinth fish and possess a special respiratory organ (the labyrinth) that allows them to breathe atmospheric oxygen at the surface. Native to Asia and Africa, they include popular aquarium fish such as bettas and gouramis, and are able to survive in low-oxygen waters. They are an order of air-breathing freshwater ray-finned fish with three suborders, eight families, and at least 350 species. This order is the sister group to the Synbranchiformes, with both comprising the monophyletic clade Anabantaria. Anabantaria is a sister group to the Carangiformes, with the clade comprising both being a sister clade to the Ovalentaria. This group of fish are found in Asia and Africa, with some species introduced to North America. These fish are characterized by the presence of teeth on the parasphenoid. The snakeheads and the anabantoids are united by the presence of the labyrinth organ, which is a highly folded suprabranchial accessory breathing organ. It is formed by vascularized expansion of the epibranchial bone of the first gill arch and used for respiration in air. Many species are popular as aquarium fish - the most notable are the Siamese fighting fish and several species of gouramies. In addition to being aquarium fish, some of the larger anabantiforms (such as the giant gourami) are also harvested for food in their native countries.