What is it?

[mojo jojo]

My tank is currently cycling. (since Dec 28) I have around 20 pounds of live rock in it. Last Thursday I lost my damsel and two clowns to ICK.
They were in there for over two weeks, but still got sick. The question is... The other day my wife and I were looking at all of the neat life on the rocks, when I noticed a large black slug like animal in the within the base rock. It was at least an inch in diameter, It was flat and had antenea. It didnot have a shell but it resembled a snail or slug. I didn't put it in there, but it is there. What is it?

 

[fshhub]

sounds like some type of nudibranch, probably came on the rock, i woudl not worry too much about it, it sounds as if it is safe, nudis generally only eat one thing(depending on the species) and if it is still alive then i would have to think it does not need corals for food
and if you lost fish due to ick, i would not onlly wait out the cycle, but not add any fish for at least a month, so to kill off the ick, a month at the minimum not 3 weeks or so
HTH