Tanked,
very hard to sex angel fish!! There are several ways tho................
Venting is the most accurate, but this involves turning the fish over and checking the genital opening. Not an easy thing to do if you have never done it before. Also hard to do with small fish!!
If the fish are adults, and spwning the one who laid the eggs is the female while the one who is guarding or patroling the area is the male....again not reliable unless you have the fish already.
Some say in young adult/adult angels that the male will have a slight bump in the slope of his forehead, but I question this.
The best thing you can do is buy 6-8 young angels, let them grow out together and pair up on their own. The pair bond will be much stronger this way.
You can also buy breeding pairs from breeders, but these fish are usually a little older and have maybe a few spawns left at best. This is the reason breeders sell them. There are a few breeders who sell pairs that are only a few years old, but these pairs tend to be expensive.
Let me know if your interested in guaranteed breeding pairs and I can check a few sources I know to see what's available.
Hope this helped.......
CM