Ha - I was so worried I thought he was originally yellow! Much less scary then.

That crazing does look like deficiency, but not as bad as I originally thought. I'm
really wary of using any chemical product to affect the ph because they can make the water too unstable and quick changes to a lower ph could quickly kill fish; I'm not knowledgeable about it's effectiveness otherwise. Using crushed coral is a natural way to go about it, but that's really a personal choice.
I know what you mean - we adore our two mystery snails as much as out fishies. They just have SO much personality!