Influence of water temperature, habitat complexity and light on the predatory performance of the dark sleeperOdontobutis potamophila(Gunther, 1861)

Recently, the dark sleeper [Odontobutis potamophila(Gunther, 1861)] was selected as a potential aquaculture target. However, the feeding behavior of this species remains unclear. In this study, we investigated the influence of water temperature, habitat type, light intensity and photoperiod on the predatory performance of dark sleepers against juvenile demersal mrigal carp [Cirrhinus mrigala(Hamilton, 1822)] in the laboratory. Our results showed that both the prey consumption and the feeding rate of dark sleepers increased significantly with increases in water temperature (22-34 degrees C) and stabilized between 26-34 degrees C. Additionally, both the prey consumption and the feeding rate were higher in vegetated habitats than those in open areas at 22-30 degrees C, although no significant differences were detected. The prey consumption and the feeding rate of dark sleepers increased significantly with decreased light intensity (0-1350 lx) and shortened light duration (0-14 h), indicating that this fish prefers feeding in dark environments. These results will help elucidate the influence of environmental variables on this species' predatory performance and create suitable protocols for its culture.