I read an article stating that most snails sold as reef tank cleanup crew members actually come from coldwater, such as some turbos, and that exceptions to this are nassirus varieties and fighting conches. There were more varireties in both the former and latter. They brought up a couple interesting points, one being their lifespans. Apparently, every difference in degrees farenhite of water, compared to their natural water temperature, their metabolisms rise, thus, they can starve if algea is not sufficient. I've always had problems with snails myself. It seems as though I've always had to replenish my stock annually. I'm wondering if this could be the cause. However, I know that hermits also play quite the role in the dissapearance acts, which is why I will not be adding them in my new build. Anyway, just thought I'd throw this out there and see what kind of inputs, if any, we can get.