they have the same genus and specis name, with the black and white having a little "var." after the species to indicate the color variant.
What about on the topic of clowns the odd number vs even number? say there are 3, is there more potential for aggression against the one if 2 pair up? I'm always seeing just a pair of clowns. I'm seeing information that the tank bred like to be in groups but not seeing personal experience on it.