sun coral
 

I got a nice sun coral with 8 heads 2 weeks ago, It has been eating since day 2 but the polyps only started to open fully 2 days ago and at night, when the lights come on they close up. Is there any way to get them to open in the day?

Where is it placed in the tank? I think Sun Corals don't like very much light. I know someone who puts his under an overhang in the "shade" and it likes it.

they aren't photosynthetic and mainly feed at night. what you describe is normal. You can however train it to open during the day; just feed it right when it first opens up, and feed earlier and earlier until you are eventually feeding during the day. it takes a while.

Agreed, takes some time but you can train your coral. Most of my LPS actually open up nice and big as soon as I turn the pumps off. My Aussie acan even opens up as soon as I stick my hands in the tank. Just keep target feeding it and eventually you can get the polyps open during the day. If all else fails buy a Rhyzo!
Levi

Its now on the sand bed of my 8 gal bio with stock lights