is it normal for a snail to disappear? the shell was found completely empty in my tank. i only have a betta, ADFs, ghost shrimp, and another snail. i'm not sure, but i don't think any of those would eat it...
Its possible that he got eaten, or died and was consumed then. Do a good search of the tank and make sure you can't find any remains before it causes you any problems
I blame the betta too. I have a couple of ping-pong ball sized mystery snails and my betta tries to bite them sometimes. When i see her gearing up to attack I tap on the glass and yell at her, then she just looks at me like I'm stupid and swims away.