I think it could very well be a warmouth/ green sunfish hybrid. When I took a fish identification class in college we were told hybridzation among certain species of sunfish is very common. Even biologists have trouble from time to time.

Working for a short time in the fisheries field and as a fish taxidermist I have seen a lot of natural hybrids. I commonly see natural bluegill/redear hybrids and I have seen and still see from time to time natural black/white crappies. They will look like one of the species of crappie but have the spine count of the other.

A pumpkinseed/bluegill hybrid is another common one up here.

The way I understand it, if prime spawning sites are limited as in a small pond than there tends to be more hybrization for obvious reasons. I suspect most state record bluegills are actually hybrids whether intentionally stocked are natural hybrids.

If pigs could fly bacon would be harder to come by and there would be a lot of damaged trees.