Effect of Different Tank Colors on Growth Performance of Rainbow Trout Juvenile (Oncorhynchus mykiss Walbaum, 1792)

Effects of four different fiberglass tank colors i.e. beige, grey, dark green and light green on growth performance of rainbow trout (Oncorhynchus mykiss) juveniles (4.88 +/- 0.71 g) were investigated in this study. The study lasted for 60 days and was conducted under actual culture conditions in a commercial trout farm using spring water with an average temperature of 14.8 degrees C. Growth performance of fish was evaluated in light of criteria such as mean final weight, specific growth rate (SGR), feed conversion ratio (FCR), energetic growth efficiency (EG), condition factor (K) and survival rate (SR). Mean final weight of fish in beige colored tanks reached 76.26 +/- 10.52 g while mean final weights of fish in grey, dark and light green tanks were measured as 64.95 +/- 6.94, 69.44 +/- 8.81 and 68.87 +/- 6.42 g, respectively. The differences between mean final weight of fish in 4 experimental groups were found to be statistically significant (P<0.05). However, no significant differences were found in terms of growth performance criteria among 4 experimental groups (P>0.05). Highest live weight gain (71.38 g), SGR (4.58% day(-1)), EG (45.25%) and condition factor (1.14) as well as lowest FCR (0.90) were recorded in beige colored tanks. The poorest values of growth performance criteria were observed in fish kept in grey tanks, while fish in dark and light green tanks showed similar performances. Survival rates in experimental groups were similar and varied between 98.25% and 99.57%. In conclusion it can be specified that under culture condition employed in this study and especially under low light intensities beige colored tanks are more suitable for rearing of rainbow trout fly.