The amount of sunlight/lack of water clarity definitely plays a role in a fish's colorization.
An example of this is there is a couple farm ponds that I fish. When the water is dirty the largemouth turn a real light color with hardly any darker lateral line to them. When the water is clear (see 6-8 foot clarity) the largemouth will get really colored up with a dark lateral line. They can change back and forth colorwise in as little as 3 weeks or so.