Nerite Snails are larger than Ramshorn and Bladder snails. They'll constantly scavenge through the aquarium looking for their next meal. They may not do this at record speed but they'll get there eventually.

Snails are great helpers in your aquarium as they help to keep algae at bay. They'll also help cleaning up crumbs and little bits that accumulate. 

These snails are approximately dime sized.