Fish growth can never be separated from the consumption of food. Chlorella vulgaris is a green alga that contains high protein and various other nutrients. The main component of Chlorella vulgaris is protein. The total protein in Chlorella vulgaris is around 42-58% of biomass dry weight. Amino acids contained include Arginine (6.9%), histidine (2%), Isoleucine (3.2%), leucine 9.5%), lysine (6.4%), methionine (1.3%), phenylalanine (5.5%), threonine (5.3%), tryptophan (1.5%), and valine (7%). Besides protein, Chlorella vulgaris also contains 51.3% if grown on a nitrogen-deficient medium. Chlorella vulgaris by 5% was also proven to increase weight gain, specific growth rate, and velocity lenght of Cyprinus carpio higher than control. The provision of 25% Chlorella vulgaris has been proven to be an alternative feed ingredient for African catfish (Clarias gariepinus). A mixture of Chlorella vulgaris and Daphnia sp can also be used as an alternative to gouramy feed (Osphronemus gourami). Based on the above studies, Chlorella vulgaris has the potential to be used as an alternative feed for various types of fish.