The Marginella snail is a small scavenger that will emerge from the sandbed to eat leftover food in the aquarium. We carry both the Common Marginella and the Glowing Marginella, the Common Marginella is pictured. These are small scavengers, with an adult size of about 1/2 of an inch. Two Marginella snails consume about as much food as one Nassarius vibex. They are not a cost effective cleaner, but they look nice.