That's a feather duster, but I'm only skilled in the zoas let's see if someone from #reefsquad, can help or call in someone that knows what may be going on!11.15....Need help with this...my goniastrea coral isn't growing. Since I've added it to my tank, only one new head(?)/pocket(?) area has grown and in about eight months that doesn't seem right. Is this some sort of harmful work growing on it? It sorta looks like a feather-duster...could this be stopping growth?