I have read that the Large Mouth bass changes its colors according to the clarity and color of the water they inhabit.

All summer I caught some nice Large Mouths, but they seemed like they had been bleached.  They were fat and healthy, but their color was washed out.

The water had very poor visibility (to me) due to a major algae bloom, and was greenish in color.  At the peak, my eyes could see no more than a couple of inches below the surface.

In September, the water began to gradually clear.  Now, the bottom is visible in three feet of water, maybe more.  Funny thing, there is still a considerable bloom of the green algae in process on the surface, and it gets very thick when the wind blows it to shore.  But below it, the water continues to improve in visibility.

Now, the once bland colored bass have become vibrantly colored with deep greens and the blotchy stripe along the lateral line vivid and distinct.  They look like those seen in the lure ads.

They don't fight any harder, but it sure is nice to see them look the way they do now.  I'm still fishing, but admit to looking forward to next spring, when they should still be displaying those brilliant colors.

It will be interesting to follow their chameleon change through the entire season.

Yeah, it is neat.

Not only can bass adjust their coloration to their surrounds, but individual bass can be different. I saw one unique female last spring that was so gravid she was almost round. She was also so buoyant the male pushed her around like a balloon. I assumed she was buoyant with eggs although I've never seen another female this buoyant. Anyway, she also had pale longitudinal zig-zaggy stripes and looked like one of those little round striped watermelons. I had to chuckle at the sight of her.

I believe it was in In-Fisherman that I read the darkness of the Bass is based on the Sunlight it recieves. This said the merkier the water+less light peneration the lighter the Bass. Much like a tan. Helps to identify the depth the Bass stage at also due to light penetration. The deeper they are the lighter they are.

They can also change to roughly match backgrounds. I kept a bluegill in an aquarium for a while. When i changed the water in the tank I would put the 'gill into a small white plastic cooler and that bluegill would turn very pale and lose all markings. When algae built up in the tank (needed cleaning) the 'gill would be dark and heavily mottled.