Slightly off topic, but I just put in 5 white cloud minnows in my 10g tank, and wouldn't you guess, I see them (or atleast maybe one that is a bit aggressive) nipping at my lone mystery snail's antennas in that tank. Obviously im not gonna remove them, but thats because I know their mouths are too small to do serious damage. I don't like how my snail hides in the cave all the time tho.
But Im seriously beginning to think that when you have a big snail that has large antennas (mine are over 2 inches), fish just cannot resist those things waving around in their face.