Ornamental fish are the most popular pets in most parts of the world. The trade in ornamental marine fish began around 1930, and has expanded significantly in recent years, with the maintenance of home aquariums and public spaces. International ornamental fish trade is a multibillion-dollar global industry, much of which is in coral reefs caught in the Indo-Pacific and Caribbean and marketed in the United States and Europe. To increase marketability and improve the quality of color and health in ornamental aquatic animals, it is necessary to use healthy and natural diets. Algae, due to the presence of chlorophyll pigments, carotenoids and astaxanthin and other beneficial compounds such as unsaturated fatty acids and high protein are a very good source for use as a main food or supplement in ornamental aquatic feed. In this review study, we will try to review the studies on the effect of the use of algae in the diet of ornamental aquatic animals.