Nerite snail health

[Scaperoot]

    Is there anything that would cause a Nerite to climb(?) out of your tank which an API or ACO test kit/strip doesn't test for? PH is typically around 7.0. I found a Nerite on the ground near the tank rack but I can't tell which tank it climbed out of. If Nitrite and Ammonia are 0, and Nitrates under 20 ppm, what else can I check for? I've found Nerites in the HOB before, but this is the first time one has fallen to the ground. 

[Lennie]

I "think" lacking enough natural growth of biofilm/algae to graze on constantly in the tank triggers it. So they can reach other places to find food but the tank has its limits unlike nature

[Tanked]

Nerites are explorers.  Yours might be looking for food or just wandering.  Mine have been in, on, and under the HOB, but otherwise haven't ventured above the rim.  They can and will spend days above the waterline.  

I know very little about snails, so I have wondered : Do aquatic snails loose some of their ability to stick to a surface when they leave the damp, humid, aquarium environment? 

[MattyM]

Might have been munching on some minerals that evaporated water left behind, and fell or something. 

[Cinnebuns]

The answer is both yes and no and mostly it depends. Each snail is different. Sometimes they do leave because there is something they don't like in the tank. Sometimes they just want to explore. I would first investigate any reason they may want to leave. I've had dozens of nerites of over 20 different species and here's some reasons I've found they leave:

1.  Water quality - this is kind of a no brainer. It's the first thing to check for any aquatic creature and it seems you've already explored this. 

2.  Lack of food - nerites are hard to feed. They typically will not accept commercial foods but rely on natural sources. Make sure the tank has plenty of natural algae. If you are concerned you can add some cholla wood. They love it. 

3.  Fear - one time I added a yoyo loach to a tank and noticed the nerite snails started leaving the tank. I should have moved the snails before adding the loach anyway but it was interesting to me to see them leave. I have also once had a snail who didn't like a betta. The betta never bothered it and the other snails were fine with the betta but just 1 snail wasn't comfortable so I put it in a different tank. 

4.  GH or PH -  make sure PH is above 7.0 and GH is 6 or higher.