Abstract: Selenium is one of the essential trace minerals for aquatic animals. It exerts the biological roles by affecting animals爷 antioxidation and immunity through the glutathione peroxidase and the selenium proteins which have a variety of biologically activities.Selenium also plays an antioxidant role to protect the cell membranes in cooperation with vitamin E. This article reviewed the effects of selenium on antioxidation and immunity, the interaction with vitamin E as well as the effects of different sources of selenium in aquatic animals.