Use of live foods for mass production of fish larvae is one of the most important practices in aquaculture industry due to better survival and growth rate as well as resistance to stress conditions. Indeed, fishes throughout their life time both in nature and in aquaculture systems are mostly dependent on small aquatic invertebrates such as zooplankton and zoobenthos. Therefore, production of cheap and adequate live foods with high quality seems to be necessary to enhance survival and growth of fish and shrimp larvae in aquaculture industry. Although artificial foods are widely used as starter food in aquaculture, planktonic organisms, especially rotifers, cladocerans and copepods are more important at the beginning of larval rearing. Rotifers are known as the smallest metazoan and apply as live food for both freshwater and marine larvae. They are very important zooplankton in feeding of larvae because of their high species diversity, easy access, small and appropriate size, relatively slow moving, fast reproduction, suitable nutritional value and ingestion of microalgae. Of rotifers, the main freshwater zooplankton assembelages, the species of Euchlanis dilatata (Family: Euchlanidae) is cosmopolitan. This species inhabits eutrophic freshwaters. Generally, E. dilatata has a lorica length of 204 µm and lorica width of 158 µm. Therefore, this research aims to investigate E. dilatata as live food in aquaculture industry. Thus, in this research three experiments were designed. In the first experiment, we studied effects of different diets (10 dietry treatments containing Scenedesmus quadricauda , Chlorella vulgaris , yeast ( Saccharomyces cerevisiae ), alfalfa meal ( Medicago .), cattle manure, poultry manure, mixture of cattle manure and poultry manure, mixture of C.vulgaris and yeast, mixture of S. quadricauda and yeast, mixture of C. vulgaris , S. quadricauda and yeast, in the same ratio by nitrogen weight) on population growth of E. dilatata as completely randomized design with three replicates. In the second experiment, the effects of different concentrations of microalgae C. vulgaris and S. quadricauda (six diets including high algal comcentration (10×10 6 cell/ml), medium algal concentration (1×10 6 cell/ml) and low algal comcentration (0.1×10 6 cell/ml) on production and growth rate of E. dilatata were investigated. In the third experiment, mass cultivation of E. dilatata (at two culture volume of 10L and 25L) carried out using two microalgae of C. vulgaris and S. quadricauda . In all experiments, population density, specific growth rate and doubling time were determined, separately. The results showed that maximum population E. dilatata density (160 ind./ml) was obtained fed on C. vulgaris following by poultry manure and S. quadricauda . In addition, E. dilatata fed on yeast and C. vulgaris had highest lorica length (153 µm) and lowest lorica length (108 µm) in population, respectively. Results also showed that microalgal type and concentration had significant effect on E. dilatata population (P 0.05). The E. dilatata fed on C. vulgaris at concentration of 10×10 6 cell/ml had the highest population density (391 ind./ml), maximum specific growth rate (0.48 day -1 ) and shortest population doubling time (1.44 day). Mass culture of E. dilatata showed that this species reached a density between 3.56 and 285.5 ind./ml depend on culture volume and diet. In conclusion, based on production and growth rate, E. dilatata could be used as a suitable live food for aquaculture industry. Keywords: Euchlanis dilatata , Freshwater rotifer, food diets, Scenedesmus quadricauda , Chlorella vulgaris