What the heck is THAT thing...

[Willydog]

Under some of my live rock I've got what looks like a clear mushroom (not a reef mushroom, but a regular mushroom you find on land) with a hole in the center of it. I just noticed another one growing on the side of the rock...again, it's clear with a hole in the top of it. But this one looks more like a tube than a mushroom.

I checked out the hitch hiker page here: http://www.reefs.org/hhfaq/pages/main_pages/faq_rock1.htm but didn't see anything that looked like it.

Anyone know what it could be? Should I leave it alone, or is it something I should try to get rid of.

Thanks.

[G-money]

Hard to say for sure without a pic, but I'd bet they are both sponges. They are not harmful in any way and add to the diversity of your tank. They are filter feeders.

[Guy]

Look very close and see if you notice another smaller hole. It sounds like a Tunicate but i would expect a second siphon.

[Willydog]

I did a search on tunicates and I'm pretty sure that's what I've got. The one underneth the rock looks a lot like the thing in this thread http://archive.reefcentral.com/vbulletin/showthread.php?threadid=44680

I was worried since they both came out of nowhere...i swear they weren't there a week ago.

Thanks for the help