I have two mystery snails and a goldfish on the same tank. My goldfish and one of my mystery snails are doing fine. I found one of my mystery snails on her back at the bottom of the tank with the trap door mostlyclosed. I put her right side up and left her away from the other animals so she could relax and hopefully come out of her shell. I left for a few hours and she is now floating at the top of the tank. Her trap door is closed I believe all the way now. Should I be concerned that she is no longer alive or is she okay? Is there anything I can do to help her? She was doing fine on Tuesday and Wednesday eating normally and hanging out with the other snail.