hey i have a hammer coral that has clown fish living in it. it look really healthy probably the size of a grape fruit with a dozen head. do you really need to feed them or can they survive off the light, i have 4 48'' t5s( 2 10, 000 k and 2 actinic). i also do a 5 gallon water change a week in my 55 gallon tank. people say you have to feed em and people say you don't. my lfs say he never fed his lps and they do fine. what do you guys think? thanks in advance.