How Do I Know If My Nerite Is Dead

S/he's definitely still alive at present then.

I have two elderly nerites, the eldest of which on occasion goes for long stretches of time even up to a week not moving at all and seemingly dead, the youngest of which might spend a couple of days at a time not moving at all.  I definitely wouldn't worry about a nerite not moving for a couple of days but, if it hasn't moved from one weekly water change to the next, I'd carefully lift it up at the next one to give it a sniff - either it will smell (allegedly stink from what others have said on here) or it will 'collapse' and only the upper/outer shell will remain.

Having had an additional tiny nerite which arrived literally attached to the back of my younger nerite, I spent a week or so wondering if it was alive as it didn't move much after the initial couple of days.  I lifted it up daily but no smell.  Eventually, I lifted it again, only for its ?trapdoor / cartilage-like part to 'collapse' and fall out, leaving only the upper/outer shell.  There was no smell and I'm not sure what happened to its muscular innards.

Hope that helps.

Thanks both, I knew about the sniff test but hadn’t quite “gone there yet” Its very useful to know that it might detach from the shell. I think I need to do a daily/every other day lift, wiggle (to see if the body loosens from the shell) and sniff test - thanks.

Snail came out today after three days with no movement - even within the shell - the snail also wasn’t “clamped shut” properly. The smell was… interesting…. So think it was on its way out for a while and now the final moment has come.

I’ll look to get a couple more snails to replace it (it was my last one) in the next few days.

No I just meant I removed it from the tank.

Essentially you are correct in that it would move a little bit then not for a couple days but when I say move a little I mean the snail itself would be in a different position in the shell - it hadn’t moved around the tank at all for a couple of weeks.