I have a shy tropical lobster (E. debelius) who hides his pretty red/purple carapace when the lights are on, but is fun to watch with a flashlight. I imagine that with aggressive feeders he'd be snatched up during one of these latenight shows, but as long as I feed him he hasn't bothered any of the fishes, which I image would be easy considering the small blue damselfish who sleeps in a cave. I think he has eaten a cleaner shrimp and several hermits, plus many bristleworms, amphipods and other desirable critters. I've had him for about 2 years.
VERY shy but cool nonetheless...I figure in 20 more years or so he'll be ready for eating!
YBYW