Here's what I thought looked better. I found the blue mane and red tail very unappealing, because not only were they opposite saturated colors, but they were on the opposite sides of the pony. Here, I desaturated the blue, put both colors on the mane and tail, and added black to make them more cooperative. I tried to leave everything else untouched, since I personally only had a problem with the mane/tail.

This is only a suggestion, because I don't consider myself an expert on design.