Dipnoi, like Coelacanths, are also a group of fish within the clade Sacropterygii. These fish are commonly known as lungfish because of their modified swim bladder which is used for gas exchange instead of primarily buoyancy and swimming. These fish go up to the water surface in order to take in air and can survive in oxygen deficient pools of water by switching to the breathing of atmosphere air. Although mostly fossilized, there are six extant species identified to be living in Africa, Australia, and South America.