I was cleaning my tank this morning and saw something hanging off the rim of the tank. I saw a couple of sharp legs, and thought, "Holy crap! Do I have bugs crawling around the tank???". So I tried to grab the legs with some tissue paper, and it slipped down further into the tank. I then noticed as I looked closer (now that it's below the black plastic rim), that it was a crab! I don't know how it got there. I never bought one or put one in. I'm beginning to wonder if it stowed away on some live rock and I didn't notice until just now. I'm very surprised. Just thought I'd share. I have CRABS!!! Or at least, a crab. Hehe.