Just for those of us too lazy/scared of the internets to click on links.
Yea that's a decorator. I had one with longer legs in my tank. I found him on my acros devouring all those delicious SPS polyps at night. He had some kenya trees growing on his back too, since he was decorating with them. After seeing the damage he did to some specific corals, I pulled him out, showed him to a few people around town, then gave him the flush. I should have found someone who wanted him, maybe for a FOWLR, maybe for a fish that eats delicious decorator crabs, who knows.
That was the one time that I wish I had acro crabs living in my colonies, because it would have been the most bada-ssedest thing in the world to see the acro crabs defend their colonies from this polyp muncher. Oh well.
Mine was a good 1.5-2" across standing on his legs. He started small like yours, and I had seen him pick polyps, and thought nothing of it. I figured he was too small to do any real damage. 2 months later, I noticed some of my colonies ****ed off, watched at night, and this sucker grew to twice the size as before or more.
