not sure

[pipatic]

not sure where i should ask about this but,what is this lovely lookin thinghttp://www.ultimatereef.net/forums/uploads/post-3-1138112924.jpg

[LeslieH]

It's a chromodorid nudibranch, a sponge eater. Did it come in on live rock and do you know where the live rock is from?

[CaveManNOhio]

That is a very cool critter. Suck's if you like or have sponges, from what LeslieH is saying

[romunov]

Fortunately, they're very picky about their diet and will not likely eat a whole array of sponges.