They are holding this little guy for me, too. This one they said is from the Carribean, it's very tiny, you can get an idea from the finger in one shot. It is holding itself to the bottom of the critter keeper and the rock on top of itself at the same time. They said they haven't seen it out in the open at all, it's only been there a few days and the kid on staff didn't know if it had eaten, yet. The big question for me is, is there a way to tell if it is a merc or a joubini?