Effect of environmental color on learning of Nile tilapia

•Environmental color may interfere with performance in learning tasks.•Black and green environments are the most suitable for maintenance and learning test.•Blue environment negatively impact individual performance in learning test. 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