As a accomplished aquarist, I must say that you Need ,with a capital N, need to understand PH difference in aquarium water to be able to breed fish sufficiently. I have tried hundreds of times to breed livebearers to feed my snakes and frogs but they would never have many babies and the babies would never get very large. You need to make sure that the water is alkaline (PH of 7.0) for the fish to breed large scale. This is easily done if you keep limestone in the aquarium. Also, Keep the temperature in the 80's for quick breed and quick growth. Embrace algae, as long as it isnt blue-ish colored, keep bushy plants, feed mosquito larvea (leave a bucket of water outside) and occasionaly boil some lettuce leaves and put them in the tank (the fish are omnivores).

This goes for:

Guppies (Endler's Guppies included)
Platies
Mollys (thought they also like a little salt in their water)
Swordfish