Colors don't seem to mean as much as we would like. I have been trying to say that when Casper turns red he is upset but I really have no proof. Color most of the time has everything to do with environment. trying to blend in. He doesn't have to be the same color as things around him but the colors and blotches will fit in to there environment. I am going to grab a pic of Casper that shows what I am talking about.