Hmm, interesting. I had MTS years ago, loads of them in my Malawi tank; but I got rid of them all when I removed all substrate from my tank (it's bare bottom now). Perhaps he was in the filter and survived.
I put 2 small clown loaches in my 55 gallon snail infested (hundreds of them) tank and 3 days later I could not find one snail. When the loaches get too big I will give them away
Weather loaches will eat them too and won't out grow a 55gl. At least mine does. he ate my assassin snails and I don't have any pest snails in that tank.
If they are all MTS they are the very devil to remove entirely. I have totally stripped a tank, cleaned every plant and piece of wood and put all the sand and gravel in the sun on concrete ( in our hot Queensland summers no less) for over a week, only to have MTS re-emerge and take over my tank again. Unfortunately it seems even my Pakastani loaches are no match for them, that or the loaches just don't like the taste of MTS and prefer the rams horns snails.
I now am resigned to the fact that every so often especially with my tanks with sand I need to do netting raids through the sand, sifting out the sand and leaving the snails in the net to be disposed of.