They are certainly different. How's that for starters? The cow fish is similiar to some box fish in that when they get spooked they can let off a toxin in the water that can kill off other fish as well as themselves. This is also true when they die(with the exception of themselves
) . However, I do know of some that have kept this fish with none of the above problems. Good water conditions are very important. Certainly a conversation piece in any aquarium.