Corals move about as free-living creatures during their larval phase, only settling down into a semi-stationary lifestyle when they mature. Because the adults are largely immobile, corals have evolved with a number of adaptations to overcome this limitation. Coral moves when it eats, breaths and reproduces.
Many corals live inside hard, sedentary structures that resemble external skeletons, so they do not move very much. However, the creatures living inside these protective encasements must move to capture food and release reproductive cells. According to the Shedd Aquarium, most corals have collections of tentacles that extend out of their shell to grab passing bits of food. The primary food source for corals is microscopic sea life called plankton. Additionally, corals are broadcast spawners that release sperm and egg cells into the water column.