Florida gar

So I got an order of 6 Florida gar, about 4 weeks ago. sold them all bar one Im keeping as it came very silver with barley any markings and over the past 4 weeks it’s getting whiter With more red/ maroon markings fading . It come from a tank with dark substrate all others look like normals Florida , pic on left one Im keeping is 2 pics on right is it platinum or stress as it’s been like it since i got it