Anybody have a decorator crab?

[el tigre]

I've gotten a few frags of zoas over the past few weeks that have stopped opening suddenly. They have been closed for about a week now. I thought it may have been pests but I have dipped them all twice in hydrogen peroxide and water then some revive and didn't see any change in their behavior over the past few days. I noticed that my decorator crab stole a few polyps and stuck them on his head. He walks over the coral too but I don't know if it is enough to keep them closed for this long. He only sticks zoa polyps on him and they are the only ones that are closed.

Nitrate, nitrite and ammonia are all 0, sg 1.028 and pH 8.2.

Any thoughts?