Corals can obtain food in a variety of ways. Reef-building corals rely on the photosynthetic products of zooxanthellae for the majority of their nutrients. However, corals also capture zooplankton for food. Corals are suspension feeders. They utilize two main methods of prey capture: nematocyst adhesion and mucus entrapment (Sebens and Johnson, 1991). Nematocysts on the tentacles and mesentarial filaments can be used to sting prey and move it into the mouth. Some corals will trap prey in sticky mucus on their tentacles and move the prey into the mouth using the mucus and cilia. Prey size is correlated to polyp size (Sebens and Johnson, 1991).

Most corals feed at night. This may be because night is when the zooplankton travel into the water column and become available for capture. Keeping the tentacles retracted during the day may also help corals avoid predation, protect themselves from UV light, and avoid shading their zooxanthellae.

Prey can be brought into contact with the tentacles by direct interception (the flow of water makes the particles impact the tentacles), by inertial impaction (momentum of dense particles makes them deviate from the water flow and impact the tentacles), and by gravitational deposition (gravity causes heavy particles to fall into the tentacles) (Sebens and Johnson, 1991). Regardless of the method of capture, prey is moved through the mouth, down the pharynx (gullet), to the gastrovascular cavity for digestion.