Abstract

This study investigates the effects of environmental color on learning capacity of Nile tilapia, Oreochromis niloticus. Eighty-four tilapia (12.81 +/- 0.38 cm; 35.98 +/- 8.33 g), were separated into six groups of fourteen and housed in blue, green and black tanks. The fish were acclimatized to their respective colored environment for 15 days. Learning tests were performed using T-mazes color-matched to the respective fish tank colors for 15 days. The fish were then tested in T-mazes of different colors from their tanks for another 5 days. The learning task involved exploring the maze in search of a reward (feed pellets) and associating a visual marker with the reward. Results showed that in color-matched mazes, the fish in black and green mazes required eleven days to learn the task (p < 0.0001), while those in the blue maze failed to learn the task (p = 0.101). All color changes affected fish performance at learning the task (blue p = 0.101; black and green p < 0.0001). Our results suggest that environmental color influences learning, with black and green environments being to be the most suitable for both maintenance and learning by Nile tilapia.