This was the first coral I put in my tank and about once a month it looks like its dying. It looks like that for a bout 2 or 3 weeks then it comes back? but all of my other corals look fine during this cycle.
This coral can be finicky. Some people claim that they go through cycles of die off and then re-grow. It looks fine right now.
What are your water parameters, I believe these guys are sensitive to alk changes.
I'm on the rd right now, the picture is when it was good. The "die off" just happened this morning. I checked my water last night my nitrate was around 3 alk was 3.89 and my calcium was 440