Nerite stopped eating

[Briggan]

Hi!
So recently I’ve noticed my zebra nerite (housed in a 2.5 gal tank with one male betta and plenty of algae, I know it’s a tight squeeze) has stopped cleaning the algae off the tank walls, plants, and gravel.
I’ve seen him hanging around the filter (not on the intake though) and he had hardly moved for around 3 days.
I read that when there is a lot of algae and the snail doesn’t eat but seems to be still alive, it means they are happy, or something of the sort. Is that true?
I don’t know how long I’ve had him, almost a year I think. I was worried he was dying, as I know they don’t live very long.
He has lived peacefully with the betta for as long as I’ve had him.
Any tips or ideas are appreciated.
Thanks!

 

[Colin_T]

When snails stop moving about and close their operculum (door on their shell), it is just about always poor water quality or some sort of chemical in the water.

Check the water quality for ammonia, nitrite, nitrate and pH.

Do a 75% water change and gravel clean the substrate every day for a week.