+1 but it greatly depends on the type of coral your asking about.
IMO/and experience it is best to feed at night wether broadcast, feeding the entire system, or spot feeding which is more recommended. At night most coral open and catch food or nutrients floating around the tank, hense the broadcast feeding. Some use reef snow or rods, or like what 1guy stated while feeding the fish. With the fish feses (poo) it's High in Nitrogen (N) and the corals seem to thrive on this.
With that said, some corals are photosynthetic, they require lights only, some strong like high output (strong t5's or metal Halides and now LED's.
Other corals like brains and bubles and some acons you can feed them small chunks of shrimp and scallops. Remember, small chunks only, once a week.
There is a thread on the types of corals and the care needed for them. Be aware of fish stores telling you things, they are not always accurate with there information.