Hermit Crab Anemone

Calliactis polypus

Calliactis polypus, commonly known as the Hermit Crab Anemone, is a unique sea anemone species that often resides on the shells of hermit crabs. It can grow up to 8 cm long and is characterized by a wide base with wavy edges and pink striations. The column is wider at the base and features pale brown and white patches with longitudinal striations. Its oral disc is adorned with several whorls of long, brownish translucent tentacles that have paler bases surrounding the mouth. This anemone is found in the Indo-Pacific region and the Red Sea, typically inhabiting the neritic zone at depths of up to 25 meters. It is a sessile organism that forms a commensal relationship with hermit crabs, such as Dardanus gemmatus. The hermit crab actively encourages the anemone to attach to its shell by tapping and massaging the anemone's base until it detaches and can be relocated. The Hermit Crab Anemone's reproductive process involves the shedding of mature gametes into the coelenteron, which are then spawned through the mouth. The resulting zygote develops into a planktonic planula larva before settling. The species has not been evaluated for conservation status by the IUCN.