Bass like to turn the color of there surroundings, if they are on a dark bottom they will be dark, if they are on sand they will be light in color. The bass that come in from the deeper ocean water have a dark color, and that neat purple tint to them, these are my favorites. U may be fishing a dark colored bottom,(mussels, eel grass, rocks, mud) and catch a light colored fish, this is because the fish has been holding in the other area for a while and didnt settle in to the new location. These are just my observations over the years.