All of the green sunfish and the BG X GS hybrids have an orange to orange/yellow border on the caudal, anal and posterior portion of the soft dorsal fin. Purebred bluegill lack any bordered coloration on these fins.
An interesting side note: The so called Georgia Giant that is touted as a "super-fish" in some circles has this orange border in all of the web-site photos, but the picture that claims to depict a 5 lb. specimen lacks the border. Maybe once they reach 5 pounds the edge of the tail falls off!
