you will experience agression in the beginning because the female will let the male knows whos boss since she is already established in your system........after the first day or two the female will accept the male in the tank and they will coexist.....this is my experience with introducing tangs into a DT at different times....regardless of male or females Its always best to introduce them at the same time....I wouldnt worry too much about her aggression at first she will not kill the male she will just shake him up a bit for a couple of days just to give him a fair warning....aloha Les @ WPH