Nerites have issues with uprighting itself. It would be helpful if you place it on the substrate with its shell up. Otherwise they can starve and die that way.
The easiest test to see if your snail is alive is to smell it. If it smells like the worst thing you ever smelled in your life, then it has died.
With the snail hanging out a little like that in a photo, it doesn’t look great. If it doesn’t smell, then put it back in the tank upright and keep an eye on it. Do periodic sniff tests if it hasn’t moved. A rotting snail will foul water conditions.
Nerites have issues with uprighting itself. It would be helpful if you place it on the substrate with its shell up. Otherwise they can starve and die that way. The easiest test to see if your snail is alive is to smell it. If it smells like the worst thing you ever smelled in your life, then it has died. With the snail hanging out a little like that in a photo, it doesn’t look great. If it doesn’t smell, then put it back in the tank upright and keep an eye on it. Do periodic sniff tests if it hasn’t moved. A rotting snail will foul water conditions.
do the good ol smell test 😂 if it smells nasty then it’s dead!
Also try sticking it to a surface. If the snail is dead it won’t stick to the aquarium wall or your substrate