Before conducting the experiment, we allowed the territory holder fish to rest (meaning they did not have any contact with other fish) for a period of 24 hours in the water with each respective caffeine concentration. The intruders also rested for a period of 24 hours with normal tap water (without added caffeine). After the resting period of 48 hours, we obtained a territory holder and an intruder fish, and placed their fish tanks side by side so they could see each other. We observed their behaviors for a total of 5 minutes with 10 seconds in between recording the aggressive behaviors of the fish with a check mark, each one indicating that the territory fish has exhibited a certain aggressive behavior. Each experimental group was repeated for two trials. After repeating this process for all four experimental groups, we used a t-test to see the differences in behavior between the control fishes and the fishes with varying caffeine doses.