I don't see why the mineral oil would hurt. Like i said it works on the mites in those problem areas where they get under the scales. I have never covered a whole snake with mineral though but i don't see how it could hurt. As far as the oil getting in the water should not hurt either. They may dirty the cage a little faster as mineral oil is used as a natural laxative. I have gave mineral oil to impacted snakes before through a syringe.