damsel changing color

[vonstan]

My blue damsel all of a sudden (only his his back half) changed from bright blue to navy blue. Now his front half is bright blue and his back half is navy blue. Does anyone know why? He is still eating and looks ok..in fact he looks cool..I took a few pics..I never heard of this before happening before in a damsel and was wondering if its permanent or what is going on...any input would be appreciated....I will probably post his pic on the board...