Calling all perch experts...

Dr. Google has not produced any answers and I don't recall seeing anything on the board about this topic.

I noticed the other day, my pond perch seem to be less vibrantly colored than those pulled from the bottom of Lake Erie. By this I mean mostly the vertical bars do not appear to be as dark of a black and appear to fade quicker. First glance maybe look a bit more like a SMB than a YP.

Wondering if anyone else has noticed something like this? Or had any input on this coloration or lack of coloration?

Could it be diet? Amount of sunlight?

They fight hard, relative weights seem just fine and I am feeding Purina 2x day. The fish that I mention seem to be caught around the feeder area so I am assuming they are the feed-trained YP that I purchased as fingerlings and not those that have been spawned in my pond.

Any ideas? Just wondering if this is "normal".