The effects of the tank colour on growth performance and physiological responses in fingerling grouper,Epinephelus coioides

In this study, the effects of different background colours on growth performance and physiological parameters of Epinephelus coioides were investigated. One hundred eighty E. coioides (average weight 18.16 ± 0.07 g) were distributed in black, white and blue 300‐L tanks and fed to satiation for 60 days. The tank colour had no significant effect on the weight gain, condition factor, hepatosomatic index and specific growth rate (p > .05). The lowest amount of viscerosomatic index and the highest carcass protein were recorded in the white tank (p < .05). Daily food intake, feed conversion ratio and plasma glucose were significantly higher in the blue tank (p < .05). The highest levels of haematocrit and plasma triglyceride were observed in the white tank, while the total protein and albumin were higher in the black tank compared to the other tanks. The tank colour had no significant effects on the plasma cortisol level (p > .05). Our findings showed that colours used in this study did not evoke stress and thus had no effect on growth, but some metabolic adaptation occurred in each colour to achieve optimum growth.