Effects of dietary carotenoids were investigated on metabolism of the carotenoids, and body pigmen tation in oily bittering, Acheilognathus koreensis. Two weeks later after depletion,oily bitterings were fed the diets supplemented with either lutein, cynthiaxanthin and astaxathin for 4 weeks. Carotenoids distributed to and metabolized in integument were analyed. The carotenoid isolated from the integument of wild oily bittering, composed of 47.2% zeaxanthin, 11.4% lutein epoxide, 11.0% diatoxanthin, 9.7% lutein and 8.3% zeaxanthin epoxide. Meanwhile, two weeks later after depletion, the carotenoid composed of 29.9% crytoxanthin, 19.3% zeaxanthin, 13.2% lutein epoxide, 12.0% diatoxanthin and 8.8% zeaxanthin epoxide. These indicated that zeaxanthin, diatoxanthin, lutein epoxide and zeaxanthin epoxide were actively metabolized in oily bittering, compared to that of other fresh water fish. Total carotenoid content in the integument of wild oily bittering and oily bittering depleted for two weeks was found to be 1.72mg% and 2.08mg%, respectively. Two weeks later after treatment of experimental diet, total carotenoids content was increased to 2.23mg% in lutein, 2.36mg% in cynthiaxanthin and 2.49mg% in astaxanthin supplemented group, which were relatively higher than 2.10mg% in control group. Meanwhile, 4 weeks later, total ca rotenoids content was decreased to 1.76mg% in control, 1.95mg% in lutein, 1.74mg% in cynthiaxanthin and 1.72mg% in astaxanthin supplemented groups. These result indicate that dietary carotenoids were rapidly accumulated and then metabolized to certain metabolites shortly after feeding. Body pigmentation effects of the carotenoids due to accumulation of carotenoids in the integument of oily bittering was the most effectively shown in the astaxanthin supplemented group, followed by cynthiaxanthin and lutein supplemented groups. In the integument of oily bittering, dietary carotenoids were presumably biotrans formed via either oxidative or reductive pathways as presumed the variation of total carotenoid content and carotenoid composition in all experimental groups. The lutein was oxidized either to astaxanthin via doradexanthin and doradexanthin, or to zeaxanthin epoxide via zeaxanthin by oxidative pathway. Cynthiaxanthin was converted either to diatoxanthin and zeaxanthin by reductive pathway and then to zeaxanthin epoxide by oxidative pathway, or it was converted to astaxanthin via diatoxanthin, zeaxan thin and doradexanthin by oxidative pathway. Astaxanthin was converted to doradexanthin and zeaxanthin by reductive pathway and then to zeaxanthin epoxide by oxidative pathway. These results suggest that, oxidative pathway of carotenoids was major metabolic pathway along with reductive path way in fresh water fish.