purple tang aggression

I picked up a purple tang and didnt realize it had a white tail vs yellow. couldn't find anything about it online. hoping it will turn yellow

Hi everyone, I currently have a problem with my two tangs. They are both juvenile and from biota! Super great fish although sometimes they don't get along. Now fast forward I purchases a copper band butterfly although I knew the risks I asked to seem them eat and this one was a very sporadic...