Randy :

Many things can affect fish coloration including water clarity and chemical composition, bottom color , mating , light penetration and intensity . Color is often affected by the current situation such as the fishes status as predator or prey, aggressive or passive, agitated or calm, angered or under attack etc. Their coloration scheme is often divided in categories such as warning coloration , cryptic coloration , disruptive coloration , or countershading . Much of coloration is controlled by cells called chromatophores and iridophores which react to the various stimuli. With the acid blue and acid yellow in the dyes it can and does affect light penetration and with it fish color. You could take those same fish and put them in the no dye pond and very quickly they would change to the same color as the fish already there. See Bill Cody's post above wrt dyes effect on light filtering.