White fuzzy growth on live rock ID

[Lognor]

Not sure if this is something I need to worry about or not.  Looking for an ID and experience with whatever this is.  

[RayWhisperer]

Tough to tell by those pics. Could be bacteria, dying algae, hydroids, sponge growth, or a few other things. Try googling those I've listed to see if anything matches.

[Joevember]

I've had hydroids in my tank a while ago that looked similar.

[Lognor]

ok, I wasn't sure iof it was a type of sponge or other beneficial filter organism.  Luckily that rock isn't locked in place so this weekend when I'm cleaning I'll pull the rock and scrub it down. Thanks for the feedback.