Inverts are very sensitive to ammonia, nitrites, etc. Hopefgully you are through your cycle before you added anything, otherwise you may have 10 dead snails and 8 dead hermits in the tank - just an assumption from your post though.
Anything you feed your fish will feed your hermits, I try to drop in a few silversides, shrimp, or scallops that will float to the bottom and give the hermits something to munch on.
Keep in mind, some hermits will kill snails for their shells too, even if they don't need them.