nwaas.com

A snail vortex? Filter feeding is one thing but this guy is hogging all the food by creating a whirlpool using osmosis and pulling food towards it from the surface. I have never witnessed this behavior. I've had Apple snails for most of the last 5 years but this is a first for me. I used to have a big one that would munch his way up and extend his air tube about 6 inches before the top and get a breath when he was close then glide back to the bottom using it's foot as a wing. I thought that was odd.

Lots of snails will do that, including small ramshorns. It's easier to see what's going on with the big snails, though!