To the OP, Platties will not eat snails.

Can you keep snails with Platies?

Platies and snails would be fine together. Make sure you add some type of calcium for the snails.

Is it OK for fish to eat snails?

Goldfish

Believe it or not, Goldfish are one of the most prolific predators for snails! Nearly every type of Goldfish species, from common to fancy, will seek out snails to eat. They are more than willing to eat any snail that they can fit in their mouth. However, they will often avoid larger adult snails.