Hey everyone, my big Golden Apple Snail has developed this as well. It was extremely interesting to read this thread (and I’m sorry for all those who lost their snails, it’s nice to find people who genuinely care about their pets). But I was just going to voice my opinions on the popping of the lung membrane, I am neither doctor nor vet, but I doubt this will work. With a human, we live in the air, so when our lung is punctured like that water can’t enter it. The snail however lives in a toxic atmosphere, as water is certainly not supposed to end up in there. So far i have moved my snail into a small sick bay tank; with just enough water to cover it, but not so much that it's floating (I’m guessing this will reduce stress on its flesh, perhaps preventing it from sliding out like others have done. I'm also wetting down the lung membrane every now and then so it doesn’t dry out. I'm not going to try popping it, and I’ll just hope that it can sort it's self out, or pass quickly. Also i was thinking about if everyone whose snail developed this condition could post on this feed how it was reacting before it got it. Maybe we could identify what’s causing it. Mine was moved from a large 200L tank into a smaller one as my clown loaches has finally grown big enough to attack him (I was assured by the pet shop this wouldn't happen, should never have been so naive). So perhaps he was injured by the clown loaches, or while I was moving him (this was about three or four weeks ago)? he was put it a 10 gallon tank with one other apple snail and about 8 neon tetras. I noticed since then on he was floating on the surface every now and then, but I paid little attention as i knew that snails did this from time to time. But one night I thought about how long he’d been floating and realised it must have been close to one day, and so far that night, I also noticed that my tank was about 5 degrees to hot, so I quickly started putting a few small ice packs in there to cool it down a bit. I woke up the next morning to find his lung exposed. Good Luck everyone, am going to pay close attention to this feed to see if anyone can come up with a solution.