snail ID

[Kittycat]

Any idea what these are? Got them from an LFS for free, they just showed up when they got plants according to the owner, I figured these are likely plant-eating, but would be great if I can find more details about the species.

Also, any tips on how to prevent snails from spreading to other tanks? I put these guys in my fry tank (bare) just to clean up, but I don't want them accidentally going to my main tanks where they might eat plants and propagate beyond my control...

 

[GSD]

if you put any plants in ice cold water before you put them in it should kill any snail eggs!They look ot me like ordinary pond snails though im no expert try this!
hope it helps

http/www.drhelm.com/aquarium/snails.html