I have heard of people leaving out lettuce or some other leafy vegetable in their tank overnight and that in the morning it will be covered in snails, then just remove the piece and the snails will be gone as well. It didn't work for me, but it's worth a mention.
Other than that, decrease feedings, try mechanical removal (it's not hard to squish the little guys).
I wouldn't suggest buying a fish just to remove something and then you will have a fish you don't want in the end.