A groundnut oil cake (GNOC) based control diet (C) was prepared without the incorporation of brewer's spent yeast and marigold as natural carotenoid source. In the test diets, GNOC was replaced with 30% brewer's spent yeast and incorporated with carotenoid pigments (200 mg/kg diet) of two different coloured (orange and yellow) marigold flowers from the same species Tagetes erecta. The test diets were designated as T1 (30% replacement of GNOC by brewer's spent yeast and without incorporation of carotenoid pigments), T2 (30% replacement of GNOC by brewer's spent yeast and incorporation of 200 mg carotenoid pigments from orange coloured marigold) and T3 (30% replacement of GNOC by brewer's spent yeast and incorporation of 200 mg carotenoid pigments from yellow coloured marigold). The control and test diets were fed 60 days in an indoor experiment to evaluate the growth, survival, and skin coloration of the koi carp Cyprinus carpio L. The diets were fed in triplicates using 12 FRP tanks (250 L). Twenty fish (4.0 g) were randomly distributed in each tank. The feed was given twice daily @ 4% fish body weight. The fish were batch weighed in every 15 days interval and the feeding ration was adjusted accordingly. The initial and final coloration of the skin of fish was estimated following Oslon (1979) and Kumar et al. (2017). The experimental results indicated that there was no mortality in fish fed control and test diets. The weight gain, FCR, SGR and PER of fish were significantly better (P<0.05) in test diet groups as compared to control diet group. However, no significant different (p>0.05) was observed in these nutritional and growth parameters among different test diet fed groups. The skin coloration of fish fed diet T-2 was better significantly better (p<0.05) than the other dietary treatment groups.