So, I'm looking in this book I got from the library(yes they still exist), called Dr. Axelrod's mini atlas of freshwater aquarium fishes and on pg. 52 there is a pic of a Cichlasoma severum that is light black with dark black bars on it's bottom half and one full bar just before the tail fin. Also, the tail fin is clear. Is this just a very dark green severum or a wild variation that has never made it into fish keeping?

