The food components of red sea bream(Pagrus major) cultured in copper alloy(brass) net(BN) and nylon net(NN) cages for nine months were investigated. The body weight was 234.9g at the beginning of the culture(the young fish), and then 692.1g(BN group) and 549.3g(NN group) at the fish cultured for nine months(the nine-month culture fish). The moisture content of the edible portion of the fish was higher in the young fish than in the nine-month culture fish. On the contrary, the lipid content was higher in the latter (9.1-10.6%) than in the former (7.6%).　 The lipid content in the nine-month culture fish was slightly higher in the BN group compared to the NN group. There was little difference in protein content between the young fish and the nine-month culture fish, or between the BN and NN groups. There was a slightly higher level of copper content in the liver (5ppm in the young fish and 5-6ppm in the nine-month culture fish) compared to the edible portions (1ppm in the young fish and 3-4ppm in the nine-month culture fish), but no difference was evident between the BN and NN groups. The prominent fatty acids were 16:0, 18:1n-9, 22:6n-3, 16:1n-7, 18:2n-6, 20:5n-3, and 18:0 in the edible portions of the young and cultured fish. The n-3 fatty acid content was slightly richer in the BN group.