Blue Dumpy?

[BeckyM]

I just got my new dumpy 3 months or so ago! He is a green color, and I really want that blue color to come out in him, how do I do that safely? Thanks

He's uber cute .
Granted, I'm far from an expert on white's...but...what if you put something blue colored behind his tank, like a towel or a blue sheet of plastic, something for him to blend against, would his color alter slightly to match his surroundings or no?