Early-stage larvae of the Kuruma shrimp Marsupenaeus japonicus are cultured up to mysis stages on microalgae, including Chaetoceros calcitrans, Chaetoceros gracilis, and/or Tetraselmis tetrathele, as food sources. Microalgal proliferation is affected by weather conditions, making stable and systematic production of both the microalgae and M. japonicus larvae difficult. The Thraustochytrids are a group of heterotrophic protists that include the genera Aurantiochytrium and Parietichytrium. The Thraustochytrids contain large quantities of n-3 highly unsaturated fatty acids, especially docosahexaenoic acid, an important nutritional component for the growth and physiological function of marine animals. Because the Thraustochytrids are heterotrophic and multiply rapidly in artificially controlled environments, their large scale culture is easy, stable, and systematic. To determine if Aurantiochytrium and Parietichytrium can be used instead of microalgae as a diet for early stage M. japonicus larvae, these larvae were reared in the laboratory on a diet containing C. calcitrans or strains of Aurantiochytrium or Parietichytrium, and their survival, development, and growth were compared. Larvae fed on the KOU10 strain of Parietichytrium sp. showed significantly greater survival, development, and growth than larvae fed on other diets, including those containing C. calcitrans. Although the mechanism by which the KOU10 strain enhanced the survival and growth performances of M. japonicus larvae is presently unclear, these larvae may be stably and systematically cultured on diets containing Parietichytrium instead of microalgae.