When cleaning the inside of your aquarium with an algae magnet, it’s not just grains of sand you have to worry about scratching up your tank. Tiny banded snails, called Collonista snails, can get in between the glass (or acrylic) and the cleaning pad of your algae magnet. When you move the magnet back and forth, those grain sized snails can do just as much, if not more damage, as a grain of sand. The tank will be scratched up, resulting in an interrupted view of your aquarium inhabitants. The snail will likely survive the ordeal, which shouldn’t really matter either way since the aquarium likely has thousands of these tiny snails around.