blue with white line ID plz

[criticalencore]

I was pulling some small rocks while doing a water change and flipped on that had 3 of these and a chiton on it. Any idea if this is bad or not? Thanks

 

[criticalencore]

Here is the pic. I may can get a better one

 

[Dkuhlmann]

Stomatella snails, I thought at first. Now I'm not so sure. See if you can get a better picture when they're out and moving. Or put them in a clear glass so you can see their underparts.

 

[Betta132]

A better pic would be helpful. Capture one and put it in a clear glass full of tank water, and give it a few minutes to come out.

 

[cloak]

Blue or black with a white line kind of sound like a Scutus snail IMO. I'm not sure if this is what you have here, but you might want to do a search just to compare the pictures. Stomatella snails do come in black as well, but they don't necessarily have that distinct white line on top.