I fed my cleaner shrimp more than all the fish fish in my 40 g and he would still go around to every coral that I'd spot fed and steal their food. Some of my lps (mainly scolys) were starving to death and I didn't know why until I caught Mr. shrimp in the act one night. He grew to about 4 inches and was molting every two weeks. It was an extremely intelligent creature but, alas, no more shrimp in my tanks (made a tasty cocktail snack, ha, ha--I re-homed it). The shrimp was at least somewhat careful not to damage coral when he removed their meals, as it probably recognized that the coral was a swell meal ticket. Hermit crabs, on the other hand , will gut a coral stealing food it may have ingested. Not a hermit fan. The only other crab I've had is an emerald, which I really loved. Mostly, it seemed to be content with eating algae but as soon as it got a whiff of me feeding other things in the tank it wanted in on the party and would wave its little claws at me. I mean, how can you not feed a little creature that's smart enough to communicate its wishes? Well, after that, every time it spotted me it would go to waving its claws (and I would feed it). Unlike the shrimp, it did seem to get full and never caused much trouble. One day, I went to move it to a larger tank, lifted it out, and it just died...like it was so happy where it was it couldn't bear the reality of moving somewhere else...at least that was my take on the matter (and I still feel badly about it). Now I just have brittle stars and asterina starfish, lots and lots of both.
