Corals also eat by catching tiny floating animals called zooplankton. At night, coral polyps come out of their skeletons to feed, stretching their long, stinging tentacles to capture critters that are floating by. Prey are pulled into the polyps’ mouths and digested in their stomachs.
How often they can stretch their tentacles?
They also feel hunger because they have nervous system. That is the time they get their food.