I have to share because I know how expensive corals can be!
We had a 5 head zoa that had algae going all over it, so unfortunately, some of the heads were not opening. Went to our lfs
(well technically not local, about an hour away), and they have a beautiful wrasse tank with all of their corals that they will frag at one point. In it were a couple of Leopard Wrasse's and I freaked out when I saw them eatting at the corals! (Mind you these are BEAUTIFUL fish!) I inquired about them, did some research of my own and eventually bought one for our Frag Tank.
Put the affected zoa in with the wrasse and overnight not only did he clean up the whole thing but they started opening back up yesterday! Now mind you he is the only fish in the tank and they take a deal to get acclimated to your system so I recommend doing A LOT of research before running out and getting this coral cleaner BUT in the end, I guarantee you it WILL be worth it!