i currently have a purple tang and yellow tang in the same tank they didnt go in together but let me jsut stress that it was an absolute nightmare getting them to co-exist... if i had to do it again, no way.
My yellow is the biggest bully in my tank. She thinks she runs the place. Very annoying. She doesn't mess with my blue tang but they were added at the same time. I would love to add another one possibly a naso tang but know theres no way without somebody being injured or killed.