I know this thread is very old but... has anyone ever discovered what the cause is and how to help the snail? Mine just developed this a few hours ago and I feel terrible. I want to help him. I found him on the floor of the 10 gallon tank but almost floating facing up as if he has suddenly decided to walk like a human. I brought him up a little by hand and he mostly deflated his bubble but not all the way. He has been acting funny for the last 36 hours and now he has this huge bubble. Suggestions???