OK, been noticing that my black gravel is cleaner in the morings than at night when i turn the lights out on my 150 gal sa/ca cichlid tank, well i was watching the fish earlier and noticed a long pair of whiskers coming out from under my big rock, kept watching and a crayfish/crawdad crawls out and then backs back under it. He's about 2" long and have no idea how he's surviving with these fish, and have NO idea how he got in there, store bought malaysian driftwood and the rock. Has anyone else had any wierd discoveries like this??