The Family Fissurellidae is a group of marine snails commonly referred to as keyhole limpets. These organisms are characterized by their cone-shaped shells with a keyhole-shaped opening. Other synonyms for the Family Fissurellidae include true limpets and slit limpets. Limpets are herbivores and play an important role in maintaining the balance of coastal ecosystems. They attach themselves to rocks and feed on algae and other plant material. The diversity of the Family Fissurellidae is vast, with species ranging from the Arctic to the Antarctic. Some species are utilized as food sources by humans, while others are popular in the aquarium trade.