Angel Fish question, Sexing?

[TiffM]

Hi,
I have two almost adult angelfish. They got along well until a few month ago and now they are locking lips and the gold one is chasing the marble away from him/her all the time. I am getting a female tomorrow that has laid eggs so she is a female. I was told that the ones I have must be males to do this behavior so if I add a female and let her bond with one I can get rid of the other one. I will keep the male she bonds with and her that is fine but what I want to know is, Can my fish that I have now both be girls? Maybe that is why they fight and this could just add to the fire? I don't know but I put a lot of money into these fish and they really are cool but gosh what pains LOL. I would like them to be calm with each other and I hope this will work. How do you tell boys from girls. I have heard that you cant? I sure can't LOL. Any angel advise at all would be great Thanks!!
I have them in a fourty gal. Is that to small?
also my gold fish has a large head and the other dosnt? Could it be a bonded pair? Or would they fight if they already bonded? They are the only fish in tank.

 

[Adrian F]

Yes you can sex them the male have a big bump on his head that is call a crown and the female head is just flat so when you look at them the next time look on top of there head and you should tell I hope this helps just remember the male has a lump and the female has a flat head ok good luck and probably your angels are fighting is because there could be a possibility that you may have two female or male and female and your female doesn't like the male or it could be the opposite and theres a good example look at the picture of the person who answered first and if you could notice that the angel that he/she used that fish has a flat head so that would be a female