The most interesting and sometimes the most obvious behaviors involve interactions with other fish. Many species of fish migrate during their life cycle. Salmon and some species of eel make long migrations to spawn. This reduces competition for food and space between adults and young fish. Other fish migrate to escape cold temperatures or to find food.
Many fish gather in groups called schools.
A school is a group of fish of the same size and species moving in the same direction. Schooling may increase the chances of finding food, avoiding predators and finding a mate. It may also make swimming easier. Sight is important in keeping the school together. The lateral line may also help.