No difference whatsoever, besides shape of their tail. Though I do find that CTs often have more fin rot issues than VTs, it's not too significant.
As for blacks, they can be difficult to find in a store, but depending on where you are you might be able to find one if you're lucky. I happen to have two blacks. Brunhilda, in my signature, is a black/yellow half giant CT female and Knight is a black orchid delta. :)
Welcome to the forum, hope to see you around!
Last edited by fleetfish; 06-22-2012 at 04:13 PM.
Reason: forgot to welcome :)