Schooling of fish refers to their ability to survive and reproduce in more numbers. A school consists of many fish of the same species swimming in unison (or harmonious pattern) in the water. It is a very common pattern seen among at least 80% of the species of fish.
How Do They Travel in Schools?
The schooling pattern is almost not seen among young fish. They begin to swim in schools as they grow and it is more like formed pattern. But one may wonder how all the fish in a school travel in unison and how they know where the others are going.
They use vision as the primary source of traveling in schools. Besides this, nature has provided them with a system of receptors which resemble hair. With the help of the hair like receptors, they can sense the direction through the displacement of water.
Why Do Fish Swim in Schools?
Nature incorporated this ability in fish to move in schools and like every other nature’s rule, it also has it’s advantages
The most important object of fish moving in schools is to protect themselves from enemies. It is the same rule that applies to everyone and the same rule we were taught when we were kids. There is a less chance of being attacked when one is in a group. It is easy to chase a single fish and catch it for a predator. But it is not easy to catch a fish which is in a group. It has another benefit too. A group of fishes can defend themselves easily and this makes the predator think twice before attacking a school of fish.
There are also some ecological advantages of traveling in schools. Few species of fish secrete a slimy liquid. This helps them to reduce the friction between water and their odies. When a group of fish of the same species move together the secretions together make them move easily through the water by reducing the friction.
Besides this, fish produce a little currents (generally called “vortices”) through the movements of their tails. When they make a staggering movements while traveling in a school, because of the currents produced by the movements of their tails reduces the friction between the water and their bodies. This makes their movement easier in water.
Fish moving in a school can respond easily to the direction and speed changes. A school of fish changes the direction and speed very swiftly keeping the connection among themselves the same.
Moving in schools helps them in finding the food easily too. Since there are more number of fish, if one finds the food then all the others can also go for the same food. When moving alone, it may not be the case.