Pearl oyster

Pearl oysters (アコヤガイ, Akoyagai) are a type of deep sea creature found in. In all games, pearl oysters also are found as shells. Despite their name, they are not related to oysters but moreso to clams and other bivalves.

In New Leaf
Upon donating the pearl oyster to the Museum, it can be found in the large pool in the first room of the ocean exhibit, along with many other species of deep sea creatures. The exhibit has this to say about the pearl oyster:

"Pearls are formed when mostly calcium carbonate and protein envelop foreign substances. Pearl oysters have numerous threadlike feet sticking out from their shell opening. These allow them to latch onto surrounding rocks and are actually surprisingly strong. Their adductor muscles are edible and are considered a delicious ingredient in some foods."