Those guppies you bought as feeders were almost certainly from someone else's overstocked tank, given to the lfs to get rid of them.
Ha ha, I remember my first 4-5 babies... and the next 10, and the next 20... I have two girls that now consistently give me 25-50 babies each. They can have up to 100 at a time.
You could always cull out and rehome your females, and do a male only display tank.
Kristina
:lol: Sure, that's what you say now. Just give 'em some time though. See how much you like them when there's dozens of them, you have pregnant females about to drop dozens more, and you're sick and tired of dropping them off at the lfs just to get rid of the excess...awww, well I'm glad I saved them then...