Crab in my Brain? WARNING HUGE PICTURE!

[Keana]

I discovered this crab in my tank a couple of months ago and I have been meaning to post a pic and see if anyone knows what it is. From the little bit that I could see in the picture of your first post I thought they looked a little similar.... My crab is not in any of my corals but he does go in and out of a rock with a little hole. He is very shy and only comes out just before lights out or at night. I have seen him many times now as he is getting a little braver. So far all I have ever seen him eating is algae, and detritus. I have a pic, sorry but my camera only has 4X zoom so it's not the best.......