Crocea (Tridacna crocea) is a very distinctive marine shellfish in the bishell class, named after the orange-red markings on the surface of the shells. As a smaller member of the genus, it is still a key species in tropical coral reef ecosystems.

The oyster, also known as the bear claw clam or the five clawed clam, is a bivalve species of the oyster genus in the family of clams. The shell length of oysters is generally 153 millimeters, with a height of 117 millimeters and a width of 113 millimeters. Some larger oysters can reach a length of 385 millimeters, a height of 250 millimeters, and weigh up to 10 kilograms. The inner surface of the shell is white and glossy, and the outer shell is curved into an arch shape with radioactive patterns on the surface and small red flat spots. Oysters inhabit shallow waters in coral reefs and near reef environments, which are often exposed to strong currents and waves. Oysters feed on particulate matter such as phytoplankton, zooplankton, and other nutrients in the water.