Can I keep more then one tang?

They are cool looking. What was there attitude like along the lines of the purple?

 

The purple I picked up with the smaller yellow from a fellow reefer local to me that was downsizing and going to a coral tank. His personality was very bild at first but not much more then the yellows. I introduced them at the same time as there was already one yellow that has been in the system for along time I was leary of fighting. There was an attitude check for about an hour and I left the lisghts off for most of a day to get them used to the tank rather then other tank mates. The following day I get a healthy feeding a small ammount more and they swim socialy ever since. The most aggrissive fish in the tank is the sohal and he only aggrissive to his reflection in the glass. I think he spend more time smashing himself on the front of the tank then swimming but its a very cool fish needless to say.