tachorn

There is one big head and 3 small heads. Thanks for any info

from the way the picture was taken it almost looks like a common feather duster... Can you post a few more pics at different angles then I will be able to tell you

The smaller ones look like hydroids to me. I would scrape them away.

Thanks for the info, I have tried taking better pictures and that is the best one that I have taken. I dont have the best digital camera. So to protect the colony I need to remove the feather dusters before they damage any more of it. It looks like they are spreading, it use to be a solid GSP colony and I first noticed the spots about a month ago.

The featherduster is harmless, but those little hydroids need to go. Rip them off with tweezers.

I had a peppermint shrimp that ate hydroids, but no guarantee all of them do.