Type of feather duster ?

[squidward]

Can anyone tell me what this might be growing on my rocks ? I have a 75 gl semi reef ,I have small zoa colonies that's the only other thing that I was thinking it might be but looks more like a feathers to me.thanks in advance

 

[TommyP]

Yes, those are feather dusters.

 

[squidward]

Yes, those are feather dusters.

Cool , it looks like I have at least 15 of theses small ones on a single rock .I hope it doesn't get to crazy .