There are three different ways that shrimp move. While feeding on the ocean floor, shrimp use one set of legs known as periopods. However, these legs are fragile and are mostly used for perching. Shrimp also have five sets of another type of legs, which are called pleopods, and they are used for swimming. Finally, shrimp move backwards rapidly by using a movement called a tail snap.
A shrimp's periopods are useful when they are feeding or moving short distances, but do not work well for longer distances. This means that shrimp are better suited for swimming than for walking. For swimming longer distances or for migrating, shrimp use their pleopods, which beat in unison and propel the shrimp through the water. Shirimp are able to swim 2 to 5 miles a day using these swimming legs.
The tail snap (or tail flex) technically moves the shrimp as well, but it is more defensive in nature.When a shrimp uses a tail flex, its abdominal muscles contract, which jerks the tail forward. The shrimp moves backwards through the water when the tail is snapped. In addition, this tail snap is used to propel the shrimp out of the water when necessary.