This study determined the optimum microalgae species and concentration for the brackish water flea, Diaphanosoma celebensis, in individual and community cultures by feeding it several different diets. Six single trials (Tetraselmis suecica, Isochrysis galbana, marine Chlorella ellipsoidea, freshwater Chlorella vulgaris, Scenedesmus sp., Selenastrum sp.) were conducted at 10 psu and $30^{circ}C$. The community and individual cultures of the water flea were performed in 1-L beakers and 3-mL vessels (12-well culture plates), respectively. In the community cultures, the maximum density and specific growth rate were highest for water fleas fed T. suecica, reaching 60.0 individuals (ind.)/mL and 0.40, respectively. In the individual cultures, the most offspring and greatest life span of females were 56.9 ind. and 24.3 days, respectively, in the T. suecica trial. By contrast, diets of Scenedesmus sp. and Selenastrum sp. resulted in poor growth rates. In the T. suecica experiments examining a range of 10 to $200 imes10^3$ cells/indl. the specific growth rate of the water flea tended to increase with the amount of supplement, while the life span decreased. The maximum density and number of offspring of females was highest at 53.5 ind./mL and 38.8 ind. respectively, at 40,000 cells/ind. These results suggest that the best microalgae species for the mass culture of D. celebensis is T. suecica and the optimum concentration is 40,000 cells per individual.