I have a little place on a lake in Northern Ontario. The lake is about 1 x 3 miles. It depends on rainfall runoff to keep water levels up. It slowly drains into another lake about 6 miles away when water is a plenty....I know this because I try to kayak to the other lake every year but never make it because of shallow areas and too many dead trees and other obstacles. Very peaceful and an amazing place to view waterfowl and turtles. My little lake contains pike and bass with some smaller gamefish. It is basically a mud bottom, 10' down at it's deepest point and has several of what we call cattail islands, floating heaps of dead vegetation hosting several varieties of bushes, grasses and trees. The big fish are under the islands for the most part and the gamefish are found near shore or in some of the few weedy areas out on the lake.
One of the smaller fish is the sunfish. I've fished in a lot of places in Ontario and there isn't a sunfish that I've hooked that wasn't very colorful, bright oranges and greens. However on my lake, every sunfish I've caught is very pale, almost white, with light green vertical stripes up their sides. Even the perch seem lighter in color here than elsewhere. I never thought about it much but after reading Dawkins' Greatest Show on Earth I'm starting to think these sunfish have evolved over the years to this paler color. Am I way off here? Is there a very pale species of sunfish I haven't heard about? Are these sunfish a product of natural selection? Has environment necessitated change? I can't see what the advantage would be if paler. Has anybody noticed anything similar in other isolated lakes they frequent?