Mystery Snail - Dying or Hibernating?

HI all, for the past couple weeks I have had my mystery snail in a quarantine tank because he was exhibiting signs of sickness. He normally lives in a 5 gal with one of my bettas, and aside from my betta's initial curiosity they keep out of each other's way. He would zoom around the tank climbing on everything and was a happy snail until he started going dormant for most/all of the day. He has gone in and out of dormancy before, so I wasn't immediately concerned. At the point his behavior was worrisome (over a week of no movement) , I pulled him out and put him in a bowl with sand, fresh water, and a piece of cuttlebone. He has been on his own for about three weeks now. He "sleeps" on his side with his trapdoor partially open and will close up when I go to give him fresh water (daily). I have left him algae wafers to munch on but he never shows any interest (previously would eat them). Any advice or opinion on whether or not he is dying or hibernating?

 

Croeso welcome to fishlore violet you are correct mystery snails do hibernate and in some cases up to 3 years but its something that's not common in an Aquarium, the fact his trap door is not shut says hes not hibernating so there's something more going on, I'm afraid it's a waiting game but similar cases have proved not good, you can only keep doing what you are but if he dosnt eat its just a matter of time,

 

Croeso welcome to fishlore violet you are correct mystery snails do hibernate and in some cases up to 3 years but its something that's not common in an Aquarium, the fact his trap door is not shut says hes not hibernating so there's something more going on, I'm afraid it's a waiting game but similar cases have proved not good, you can only keep doing what you are but if he dosnt eat its just a matter of time,

Oh no, OK I will keep at it and hope for the best :/

 

Others will pick up on my post and if there's something I've missed they will post

 

Carefully lift it out of the tank & give it a sniff near the door (operculum)
A dead or dying snail will have a distinct stinking smell.