Carp which had been fed on diets containing various kinds of essential fatty acids (EFA) for 14 weeks were starved for 86 or 93 days at different water temperatures. Rainbow trout which had been kept on a commercial diet were also starved for 42 days to allow a comparison. The loss of boby weight and that of crude protein and lipid were more severe in the carp starved at a high water temperature. The decrease of lipids was due to a decrease of triglycerides, the amout of polar lipids were almost constant during starvation. These changes in boby weight and proximate composition during starvation were found to be quite different due to the difference of EFA which had been given to the carp before they were starved. Fatty acid distributions in the carp boby lipids were not affected by water temperatures during starvation and by the kinds of EFA given to carp before starvation. In the polar lipids from bodies and in the triglyceride fractions from bodies and muscles, the percentage of 16:0 decreased and those of 20:4ω6 and 22:6ω3 increased by starvation. In the case of rainbow trout, the percentage of 18:1 was markedly decreased, resulting in increases of 16: 0 and 22: 6ω3 in both polar lipids and triglycerides from bodies and livers. These results suggested that fatty acids utilized for energy during starvation are different in the cases of carp and rainbow trout.