They won't climb out unless the water is bad. Check params

 

Its a clean tank. 0,0,5. ph=7.6. temp 79. There are 2 in there. One is down cleaning the castle where it belongs. The other is cleaning the ceiling.

 

Is there a lot of algae on the ceiling? If so it could have wandered up after food. This is also pretty normal for nerites. They live in tidal pools and like open air every now and then. If you have a lid and it is moist he shouldn't dry out but if it is dryish, it only takes a few hours for them to be to dry to move.

 

There is actually no algae on the lid. Its the first night with them and I am terrified one will escape or dry out something while I sleep. I have a glass good that fits pretty well but there are cut outs around the heater and filter. I put craft mesh the best I could over those openings. It is pretty humid in there. There is always condensation on the lid. I've never had snails before.. I'm always terrified of new things lol. I plucked he/she off the ceiling and placed her at the bottom on a bridge. Hopefully he/she stays there for the night. How do I tell if its a he or a she?

 

Check your water quality. If all is ok and the hood has enough water and humidity let him.