Several diets have been proposed for Ceriodaphnia dubia, but no single diet has been universally accepted as optimal for toxicity testing. Although several diets for Ceriodaphnia dubia culturing and testing are commonly used, little or no data exist on whether toxicity varies with the diet. The study evaluated several combinations of yeast-Cerophyl-trout chow (YCT), Selenastrum capricornutum, and Selenastrum capricornutum-Cerophyl foods for routine culture performance and the sensitivity of the offspring in subsequent acute toxicity tests with effluents. The young produced from each of the seven diets were tested in 48-h acute tests with three different effluents across the generations. The results indicate that several diets are satisfactory for culturing Ceriodaphnia dubia and that the results of the toxicity tests are comparable.