I thought green star polyps were easy?

Sounds Good! Glad to hear the star polyps opened. They do take a bit, but once they are happy they stay out all the time. These are definitely one of my favorite looking corals.

 

They will close up at times sometimes for days at a time, only to come out again. May be toxins emitted from neighboring corals causing them to close or too strong a water current on them. Also from time to time you have to with a turkey baster, for example, remve any detritus that may accumulate on them. They don't like detritus/sand covering them up!

 

Well you can't blame them, I wouldn't like a bunch of poop all over me either! Hehe.

 

There is a difference in light which is already a factor in them opening up. They were purchased under mh's now you have them under power compacts. they require strong water movement and stronger light than the Tubastrea and Frogspawn corals.
Alot of times they will close and remain closed for a day or so then you will find them opening up again. Yes, they are very hardy and grow very fast under the right conditions. Also, make sure that their isn't any detritus settling ontop of them as they don't like sediment on them- and will close up and remain closed until the sediment/detritus is removed. Also, try adding Iodine(lugol's). Best of luck...

 

give them light and current

 

With the red slime now gone, thanks to everyone's advise on my other thread about that, Bruce especially, they will have a chance to spread! They are doing really well! Also my yellow polyps are growing at a staggering pace! Everytime I feed my sun coral, I feed the yellows too. The frag has probably tripled in number (in a month!!), but they have yet to leave that rock. They are the quickest eaters, second only to the sun coral.