ecology sc.7.l.17.2, sc.7.l.17.1, sc.7.l.17.3 sc.7.l.17.2 1. the wrasse, a small marine fish, periodically cleans harmful parasites from the mouth and body of the moray eel. the moray, in turn, protects the wrasse from larger predators and provides it with a constant supply of food. this is an example of the type of relationship known as