Thanks all, he sure is cool.
I've had him for about a month now. In all honesty, I have never once seen him on the rock. He hangs out strictly on the sand, picking away at it.... and seems to prefer one corner of the tank. Although I haven't observed him at night (so who knows what he gets up to!?).
I definitely considered the difficulty level of the coral when purchasing this guy. If I didn't have bryozoans growing already on my live rock I might not have got him. But if my rock can sustain this coral (or a very similar one) already I figured I could give it a shot
. It is a filter feeder so zooplankton helps.
If the coral doesn't survive apparently the crab can find a new home in a shell.
I'm pretty impressed with him, but I agree it is not something everyone should try, and for sure not something aquarium stores should bring in frequently.
-Diana