Every Red and White DS I get dies within a week or two. This last guy was doing great, and then boom... he just died. No signs, no explanation, no clear reason... I'm just swearing them off. He's still floating in my tank... I can't bring myself to accept he died. But, I'll bury him tonight because I need his tank for my other rescue who is living in an unheated QT tank.
Sorry for your loss,but doubt it's anything to do with the color.
I had a black copper from petsmart just up and die a week after bringing him home.
I know it's not the color... but I do believe that it is an overly annoying coincidence that this is the third I've had die. DS in general I've had bad luck with, but when you add the color they just croak on me. I'll do what's best for us both, and swear them off, and try to avoid DS in general.