All the Warmouth's I've ever caught, and the one I had in my 40gal aquarium, were more brown & gold colored ... than the blue & green coloration this fish is showing. Even the link that Techno2000 provided, shows a fish with red gill flap patch & little to no color edging on the fins & tail. And while the body coloration is very similar to this picture ... any number of other websites about fish ID will show Warmouths that aren't colored in this way, as well as pictures of Green Sunfish with coloration more closely akin to this picture.

That's not even taking into account the possibility of some crossbreeding potential ... and as is well documented, the Green Sunfish can & does crossbreed with many other Sunfish species. The "famous" Hybrid Bluegill is a Bluegill/Green Sunfish cross. The Green Sunfish also crossbreeds with Pumpkinseed, Longear Sunfish, Warmouth, & probably others.

... cp