About 4 months ago I purchased a small blue mystery snail from the lfs. It has grown now to about an inch in diameter and is always active. I come in my room today from school and its floating at the water surface with part of its body hanging out of the shell. Now about 7 hours after I first seen it floating there is a clearish type stuff hanging off of it. I took it out and disposed of it. I am just wondering why all of a sudden it died. The tank is a 20 gallon high with barbs. I do not know the tank specs though.