Anemonefish belongs to the extensive family of Pomacentridae and the subfamily Amphiprioninae. Pomacentridae are primary tropical with an estimated 30 genra and 300 species globally. Anemonefish live only in relationship with large tropical sea anemones. The stinging power of the anemone keeps predators away. The anemonefish secretes a protective mucus so that it can seek refuge in the tentacles. In return it keeps the anemone free of residue. This is a good example of mutualistic symbiosis. Colonies usually consists of large dominant females and smaller males. If the female dies, a males would change it's sex to female and a smaller male would reach sexual maturity. In spite of their small size, they are territorial and would defend their territory against much larger threats, such as divers.