typically, IME, only botia-genus loaches eat snails, not dojo loaches.
bort-- you are sort of correct, but it is not a good practice to encourage. fish grow to the size of the conditions within their environment, and tanks that are too small do not have the right conditions (typically) to house fish beyond a certain size. a pleco shouldn't be kept in a 10g, really. fish growth then will be stunted and their lifespans shortened. and that's not good.
that said, clown loaches are probably not a viable option here. first of all, you need at least 3 of them, really, as they are a schooling fish. if you're buying a fish for a snail problem, and not buying a fish for its own sake, you are likely not prepared to house such a fish when it needs a 75 or 125g tank in a year or so!
in any event, there ARE other loaches, besides clowns, though it seems like people forget them all the time! yoyo loaches and skunk loaches are both commonly available and only grow to 3-5" in size. plus, they're really cool in their own right! a trio of these fish could probably be acommodated in your tank, and they'd take care of your snail problem quickly! i keep both (in addition to clowns) and highly recommend them...plus, they're half the price or less than clowns!
