I caught Rio Grande Perch in Mexico that had a big hump on their heads maybe some kind of cross bred perch. Keith
Those species can't crossbreed, though. Bluegill are Sunfish, while Rio Grande Cichlids/Perch are Cichlids. Those two species cannot hybridize.
The fish is pretty clearly a standard Bluegill. I judged plenty of them the last few years for the TXFishes Multi-species contest.
Earflap, mouth size, and coloration are all standard, standard bluegill.
