You could always remove the tang and add another abosolutely last. Some can be real mean. Mine used to even pick on my starfish. Sent him back to lfs
Got another this past year, but already had a purple and kole in there ( a 155g). The yellow was the biggest. After QT, I added him. He and the smaller purple went at it for about a week. Torn fins and all. Had no issue with the kole/bristletooth tang because they were from different famlies. The purple and yellow hang out together now, but the yellow is the boss.
Got a QT tank for him to chill in for a while while you finish stocking?