I'm sorry, I think you misunderstood my question. It wasn't a compatibility question. I have been keeping a saltwater predator tank for 14 years and I actually know what I'm doing. It wasn't a compatibility problem. It was an accident. As you know, Morays are quite blind and the lionfish was feeding and a silverside was falling at the same time past his fins and the eel who is very docile and actually reef safe accidently grabbed the fin with the fish.
It is a Brazilian dwarf banana eel by trade name. (Gymnothorax miliaris is what he was sold to me as, years ago. He has lived with this lionfish for 3 years with no problems whatsoever. Through my own research, I believe him to be a bright yellow variant of the Gymnothorax meltremus instead since he has gold eyes, not blue eyes.) While, I disagree with the label of reef safe for either of these species of eels,(no matter what the lfs tells you) they are definitely fish safe.! They will eat shrimp and crabs which is why they aren't reefsafe, but I haven't had a problem with this dwarf eel taking out any of my fish and I have had him for 3 years. He is not all that big measuring only a little over a foot in length. The lionfish is massive.
Anyway, I still would like to know how much cartildge can be taken from a ray on the pectoral fin of the Russells lion before the fin will not regenerate. The 3 broken rays are about half gone each. Thanks!