I have read that you can only keep one large angelfish per tank, awhile back I seen one of Gangstarfish threads of him keeping 3 large angelfish together, so I gave it a try I now have 4 large angelfish housed together in a 180 gal and all are doing great. I have a emperor, regal, blue face and a annulars all but the annulars are 4 to 5 " the annulars is around 6" the emperor is changing it has not reached it's adult color. I will in the future be getting another large tank to split them up.