I 2nd the clove polyps. Some folks like them but they tend to grow to well and can get out of control. Google 'blue clove polyps' and you'll see all kinds of different experiences. If that were my frag, I'd try to remove them from the system by carefully applying kalk paste or removing the frag and going at them with a toothbrush. Whatever you do, don't hit them with a brush while they're in you tank. Trust me. I ended up with tiny colonies of BCP all over the place when I made that mistake.