In the animal kingdom, there are several different types of social structures. One of the most common is the school of fish. The idea of a school of fish having a leader comes from the idea that the fish are able to move in perfect unison and that they must be following someone or something. There is no specific lead fish and the school moves as one unit because all of the fish are reacting to their surroundings simultaneously. Schools of fish form when individual fish come together to create a group. This can be for protection or to better hunt for food. In general, there is no one fish that is in charge of the others. Instead, the school behaves as a unit, with each fish following the commands of the group.