Can I get some help identifying?

[Nirnex]

This came along on my live rock, it looks vaguely familiar but I can't put a name to it. I know the pic is horribly yellow, sorry I haven't gotten my lights yet (hopefully later this week).

107005

[Percula9]

Can't tell from the pic.

[jrlim]

Sponge?

[Nirnex]

I know it's really hard to tell... everything's yellowed out. It seems like a cluster of flattened tubes or cups, which are all a yellowish white to start with. I'm not certain if it's still alive or not, though it doesn't seem to be decaying like the other stuff that I know is dead on the rock.

[joeychitwood]

They could be remnants of a colony of tube worms. Are they soft and flexible or hard and brittle? Take a look at night with a red light to see if any critters are coming out of them.

[Nirnex]

They are definitely soft and flexible. Having gone in to look with a red flashlight on several nights we've never seen anything there. They do move in the current though and a couple have come off.

[badwrasse]

my guess is tube worms or fan worms

[Nirnex]

Now I guess my questions is if it is in fact tube or fan worms, are they anything I need to worry about?

[thebkramer]

it kinda looks like vermitid snails, which are harmless. they just eat from water.
if they are alive, they send out a string of mucous, collect their food and then suck it in and go to lunch
fan worms are filter feeders, but not sure if that what they are

[joeychitwood]

As jrlim mentioned, since they are soft, they could be sponges. Almost all of the filter feeders already mentioned are harmless, and in fact help clean the water column.

[Nirnex]

Thanks a ton all for taking a look and trying to help me figure this out... if I can ever figure out for sure what they are, or get a good pic I'll have to be sure to put it in here :).