I think I may have determined my problem here... I was researching Hole in the Head disease and came upon a "stray electrical current" theory. Upon testing the water I detected some.. the sources seem to be induced by my lighting and to a lesser extent my heater. I then researched stray electrical currents in aquariums and found this can cause fading in color as well as other problems. This may explain why he is nice and dark colored in the morning and then within a few minutes of turning on the light he begins to fade... Gonna get a new heater and put a grounding probe in there to see if that helps.