When I played around with the pony creator(Official and fan-made), several colour schemes make the ponies look out of place.
 
I can’t think of any canon characters with crimson red manes.

Red and black, but appears to be just a mailpony. I can dig it!

Black and red has NEVER been done before, how original.

sign  
Artists.  
Protip.  
Black and Red is a HORRIBLE color scheme. Sure, both are colors very associated with evil, pain, darkness, and all around edgy and cool topics, but together they form one hell of a eyesore, and makes your character look like a pretentious clown, not to mention that it escapes from the regular color scheme of the show, which tends to stick around a pastel palete, creating a even bigger artistic issue.  
Bottom line: LEARN TO PROPERLY DESIGN A CHARACTER.