That said, I also agree with Gerri. I find that there is a significant variation in the coloration of bluegills depending on the water conditions as mentioned. Darker tannic-stained water produces darker less colorful bluegills. I can even see a big difference when catching fish in the same body of water with different conditions. Shallow water with light muddy bottom and lots of sunshine produces pale colored fish, while I can go across to the other side of the lake where the water is 7-8 feet deep and in deep shade and the fish are much darker. I think this may be a defense mechanism to make them less visible to predators especially from above like Herons and Osprey. Just my observations...

Jim Smith