I had a butiful mutant plate coral that was actualy 2 corals grown together in to one (realy amazing)
It lived for almost 2 years quite happely in my tank and the only reason that i lost it was that my golden headed gobie decided to burry it for a week while I was on holidays.
What I found was the trick for keeping them healthy is to feed them directly once or twice a week. I would put a full piece of Krill by its mouth and it would pull it in and eat it (realy cool to watch) or suck some brine shrimp up in to a syringe and gently blow it at it's mouth.
Incidentaly a really awesome feeder can be made using a 1ft piece of rigid airline tubing, a 1 ft piece of silicone airline tubing and a large 40cc srynge.
you can suck up the food and direct it where you want.
At first it didn't seem to happy in my tank but when I started feeding it it seemed quite happy.
well that's my 0.02
Joel
Man I can't wait to get my big tank up and running
Playing in a 20 gal just isn't as much fun lol