Scientific name - Megathura crenulata Common name – Key Hole Limpet Max Size – 3 in (8 cm) Range - Eastern Pacific, Indo-Pacific Care Level – Easy Temperament – Peaceful Foods and feeding – The snail will roam the aquarium eating algae Aquarium suitability – Reef compatibility – With Caution Captive care – This snail is extremely helpful in keeping an aquarium clean by eating hair algae. If the grain of sand is fine enough, it may venture on the sand bed. There are some reports that it will eat cyanobacteria as well. If there isn’t enough algae in the tank for them to eat, offer dried seaweed. Like all invertebrates it is extremely sensitive to nitrates and copper, and even tiny amounts are lethal to them.