2 weeks ago, one of my pumpkin nerites died. It was sluggish and weak before becoming unresponsive.   
Now my yellow pumpkin is acting in a similar way.  It won’t grip onto anything or move despite me flipping it into a correct position.  
It keeps flopping to its side. I think the water currents are doing it.   
I can’t find much information online about Pumpkin Nerites, so I’m going off basic info for other nerites.   
I was told they could hibernate for weeks, but I fear this isn’t the case. This is how my other snail acted before dying.   
I don’t think it’s from old age, as I bought them from my LFS when they were pretty tiny. They’ve grown a bit in my tank.  
I haven’t done anything new. My parameters are within a desirable range. I do have quite the batch of baby guppies, but I don’t think that could have impacted the snails.  
I stopped medicating with metroplex about a week ago. I had a parasite outbreak (probably from said nerites, that was my bad for not quarantining them) but that cleared up.   
I am a fairly new fishkeeper (Started 4/9 of this year) and trying to learn as much as I can about my creatures.  
If anyone has experience with them, please don’t hesitate to comment or reach out to me. I am always willing to take any feedback.

Pumpkin Nerites dying off slowly