If im thinking right its Apstasia.. it is not a good thing to have growing.. A LFS has a 250 gl set up that they sell from, loaded with this I'm talking its all over the tank and the manager cant understand that its killing his coral.. I had told him to take a copper banded buterfly and put him in the tank to see if he will eat it or even take a rock out and put it with the buterfly fish but he has yet to do it... he wants to buy some chemical to try to kill it?? I wont buy from this guy till its gone.. Hope this helps