I've heard from a friend that apple snails will eat the eggs of other snails. While I've never tried this myself, it's an interesting thought. Apple snails place their own eggs above the waterline, so if you don't want them to hatch, you could easily remove them.
Botia striata (zebra loach) are great for eating snails, they do like to be kept in groups though and a sand substrate is best for them. They were the best snail eaters I used to have in my community tank and they didn`t grow very big either, maximum size of 4"
http/www.loaches.com/species-index/botia-striata