How do corals eat?

There are two ways that corals eat, depending on the type of coral.  The first of these is the symbiotic relationship coral has with zooxanthellae, which is an algae that lives within the limestone skeleton and tissues of the polyp and provides the polyp with nourishment and oxygen.  Other types of coral feed on zooplankton by coming out of their protective shells at night and using their stinging tentacles to grab the tiny zooplankton out of the water.