Blue-tailed Red Drum

While fishing around Hilton Head recently, I noticed something I hadn't before. The distal margins on the caudal fins of the smaller Red drum were a metallic blue. The water these fish came from was behind Daufuski Island - shallow, marsh, and very murky. The larger drum, and the drum in clear water we caught that day, had lost this coloration.
The photo does not do this color justice. It was a surprising revelation.
OF NOTE: The lateral line of drums usually extends into the caudal fin.