Clam is a kind of bivalve mollusks, having a high nutritive value and good taste. A combination of clams and food plant should provide a balanced diet.The cultivating module mainly consists of a clam cultivating unit, a microalgae cultivating unit and water recycle system including a water reclamating unit, a solid waste treatment unit like wet oxidation, a water sterilizing unit and a salinity adjusting unit. Recycled water from the water reclamating unit is supplied to the clam cultivating unit and the microalgae cultivating unit after being sterilized. Concentration of salts in the water must be adjusted by salt supplied from a mineral recovery unit in habitat module. Lost water and nutrient required for microalgae cultivation must be supplied from habitat module or plant cultivating module.Lipid profile and optimum cultivating condition of several microalgae were investigated. Total fatty acid contents of marine microalgae were higher than those of freshwater microalgae. Freshwater microalgae contained scarcely any highly unsaturated fatty acid. On the contrary, marine microalgae, especially Pavlova sp., contained a great deal of highly unsaturated fatty acid. All marine microalgae examined were able to grow in inorganic medium based sea water.