While watching the pacific scene in my IM40 at lunch, I saw the tail of my sand-sifting goby wiggle in a cave. "How cute!", I thought. "It's exploring!". After a few minutes, though, I began to get concerned. It wasn't moving! Was it caught? Well, yes -- by a predator! The front half was pretty well chewed up when I pulled it out with tweezers (the corpse went to my mini-maxi carpet), and I couldn't tell what had done it, but I saw movement in the cave. After a while, a red claw poked out. It was sort of rounded, and not pointed, and looked like a lobster claw. I certainly didn't put anything like that in my tank, but if there is a something, it would certainly explain the disappearance of a royal gramma and a peppermint shrimp. Any thoughts? Couldn't get a pic today.