I think most people using CO2, have come close to this at some point. I've had it happen at night once. 40 japonics shrimps decides to leave the open top tank. When I woke up, all fish were gasping at the surface and found shrimps everywhere. I immediately changed half the water and added a little H2O2 for extra oxygen. All fish survived.
Like you mentioned, snails don't take it very well either. In fact, I think all invertebrates are more sensitive than fish. To get rid of snails. Rinse your substrate with carbonated water. Do the same with your plants and they'll all be snail free and ready to go back in your tank! Do this with all new plants and you can keep your tank snail free quite easy