I love these zoas, I wish this didn't happen to them. I do not have this anywhere else in my tank, and I believe this came with my frag. If anyone can tell me how to get rid of this, I'd greatly appreciate it.
Try taking, say 3 blue leg hermits, a bug container and the frag with some sand to support it up right. Let the crabs go to town, leave for a week so the zoos heal over the algae bases, re place to original spot