If you are willing to put in the effort, I strongly recommend making some snail jello as bait. All you need is a 5 ounce jar of baby food (vegetable flavors work best), one packet of knox gelatin and some fish food. The recipe is in a sticky at the top of the Invert page. Since you will be discarding the snails you can omit the calcium. This will be covered in snails which you can discard.