Swollen/bloated Snail?

[AnakBettaMoon]

Ive a mystery snail and i found him this morning all bloated and swollen and puffy looking, he looks like he can't close his little trap door.. could he have just gorged himself? cause my water hyacinth is dead this morning too...
hes just sitting at the bottom of the tank with his door closed as much as he can, i took him out and touched his door he twitched a little but he is obviously swollen... Ive never had a snail before i hope this isn't a stupid question..

Also i think he ate the other little snail in my tank... normal?

 

[Donya]

Ive a mystery snail and i found him this morning all bloated and swollen and puffy looking, he looks like he can't close his little trap door.. could he have just gorged himself? cause my water hyacinth is dead this morning too...
hes just sitting at the bottom of the tank with his door closed as much as he can, i took him out and touched his door he twitched a little but he is obviously swollen... Ive never had a snail before i hope this isn't a stupid question..

Also i think he ate the other little snail in my tank... normal?

If it's a mystery/apple snail, I'm assuming in a freshwater tank, you might get more help in the freshwater sections. Anyway, your first idea could be the case - it's quite common for well-fed snails to not close up completely. Just to be safe, you might want to test your water for ammonia and nitrite though, since, in apple snails, swelling of the foot is often an early symptom of elevated levels of those chemicals.