These snails are amazing. So, I decided to mess with my Mag 7 return (was making noise due to impeller issue). off topic, Now pump still runs but not pumping . Lesson learn!., don't mess with it until you have a replacement! Find a bunch of pumps but none fit the return tube. The one that fits is too weak to push any water!
Okay, back on topic. I found 2 nerite snails behind my tank. bone dried (possible been there for days), but the black piece that cover the snail (don't known what it call) is still intact. So I tossed them back into the tank. Within 30 second, I see both snails came out. Great survivorsl!!!