Angelfish are breeding!!

[Xtasia]

My angelfish are breeding and it appears that there are 2 sets of pairs...

I read that it was diffcult to tell the male and female apart, but that it couldbe done by looking at the exposed nipple like genitals while they breed... to me, they look exactly the same (but I'd like to be optimistic and believe it is my niavete and not that my fish are lesbians)... Is there any sort of behavior, or fish shape I could use to differentiate sex?

Also, how close should the air bubbles from the air stone be to the eggs if you grow the eggs away from the parents?

More questions later I'm sure..

Thanks for any answers