The butterflies would eat the corals faster than they could grow..you could give them a mix of diet though...some pellets/flake/ and also let them eat corals...IMO i wouldnt spend that much of corals to let them eat...yes some people buy live food, such as feeder shrimp, this you could buy 100 shrimp for 20-30 bucks...as far as live food (fish) you would buy a goby, but this is a one or two time thing usually to get the fish, ie lionfish, to start eating again...you really dont want to feed your lionfish live fish all the time, because then he will get use to eating fish, and perhaps some of your display...IMO it is not an inhumane way of feeding a fish, because that is nature, but like i said I wouldnt want to spend hundreds of dollars on corals for the butterflies to eat, and even then not have enough food...UNLESS you do the "blender" trick on mushrooms and have them eat a bunch of mushrooms...other than that, i cant really help you out much more...