Hi. I am trying to learn more but this is what I know:
That the females are larger and that their anal fin is straighter. - I think it goes down perpendicular to their body.
Males are a bit smaller and their anal fins are crescent shaped.
( anal fins are the red fins on SDs)
When they mate the male and female will swim/ wiggle alongside one another. The female will then release hundreds(?) of tiny clear eggs.
If you want to breed them to raise the fry I think you need to put the pair in a separate tank so other fish do not eat the eggs. I think they hatch after 4 days and can swim a week later. ( last part about breeding I am not so sure)
I hope that helps. Sorry I don't know more. I will share more info when I get more.