Hi
I am not any expert either but I have always thought that most species have their markings/colors influenced by their surroundings, substances present in the water and diet. As a kid, we fished for sunfish and bluegills in a river tributary very close to the Chesapeake Bay. Those fish were very bright and beautiful however, the fish we have stocked in our mountain pond are not nearly as bright. They are healthy and have increased in size over the years but the colors seem dull to me. I am thinking that perhaps we need to add some more minnows and fresh water clams to improve their diet. In WVa spring comes late and winter comes early so maybe the amount of sunshine and warmth may be a contributing factor too.
Some waters where there is heavy tree canopy and there is tannic acid in the water, the fish are darker. This is an interesting thread and I hope some more folks will join in to share their thoughts.
Gerri