loaches and snails don't mix. loaches will eat snails. and even if the snail is large, the loach will chip away at their shell to get at the meat. they can chip away at rock and shells by "popping" their jaws. if you hear popping and clicking noises coming from your tank, check on your snails.

i have a 150 gal and my clowns decimated my batch of snail breeders.

look here for lots of info on loaches: The Loach Almanac — Loaches Online

good luck and keep us updated!