What's this?
 

Hi Canreef,

Here's a photo of something growing in my tank, wondering what it is but havent been able to find anything online, was wondering if someone on canreef had an idea.... It's that thing that appears to have barnacles around it...

http://i.imgur.com/HreNi.jpg

Woa that's ONE BIG picture

Sorry, for some reason I cant get the canreef system to shrink it down, even if i change the original image thats being hosted

Colonial ascidian, like a tunicate. I would not be concerned about it and have tried to get some going in a tank once only to have a Koran angel gobble them all up. IDing it even to genus would take some time though.
Dan

If you mean the critter in the middle of the 'barnicles', it could be a Chiton

+1

Chitons are mobile and have a mantle with 8 plates on their back (although the plates are often not visible). I would bet you guys this is stationary and semi translucent. The barnacle looking things are siphons from each of the colonial ascidians. I'd bet you a frag on it :)?, but I have to warn you I am about 99% sure on it (given the limited photo),
Dan

I'm just going by what I can make out in that rather monster and blurry pic :smile:
Perhaps aquatechy could tell us whether or not the thing in question is mobile ?