White thing on hammer coral

[Ssdangeranger]

This white thing has showed up on my hammer coral. It easily comes off and is sort of like cotton? Is it harmful? Is it part of the corals growing?

 

[scsdukefan408]

Can't tell from picture but maybe a sponge...if it is you can just take it off don't leave it

 

[Ssdangeranger]

Yeah I'm not planning on leaving it. I think it's irritating my coral. It's not out in full expansion like usual and I think that's the problem

 

[scsdukefan408]

Yeah had some sponges on my Zoas and they basically smothered them