During the feeding of the fish, a hand was applied to the glass of the aquarium, and after feeding

During the feeding of the fish, a hand was applied to the glass of the aquarium, and after feeding, they were removed; after a while, the fish swam to the brush without food. Explain the result of the experiment.

During feeding, the fish intensively produced gastric juice, and, since at this time a person put his hand to the glass, the fish “remembered” that is, they formed a conditioned reflex. Therefore, when a person once again put his hand to the glass, the fish automatically developed gastric juice, they felt hunger and swam up to the glass.