I was looking at one yesterday at my LFS. The guy there told me they sift sand well and leave fish and corals alone and they stay fairly small in my size tank. I was wondering how big they get. I saw on liveaquaria that they get 2 ft. My tank is a 65g and I don't want one if it gets over 4 inches let alone 2 ft. Do they bother snails, crabs, or shrimp? What is everyone's opinion on these guys? Thanks