Common name: giant green anemone

General information

The Giant Green Anemone, Anthopleura xanthogrammica, is a large and striking sea anemone native to the Pacific coast of North America. It is known for its vibrant green color, which is due to symbiotic algae called zooxanthellae living within its tissues. These anemones can reach a considerable size, with some specimens measuring over 30 cm in diameter.

Care

In the aquarium, Anthopleura xanthogrammica requires a stable environment with strong lighting to support the photosynthetic needs of its zooxanthellae. Moderate to strong water flow is also important to mimic its natural habitat and to keep the anemone healthy. It is a hardy species but should be introduced to well-established aquariums to ensure it receives the necessary nutrients and has a lower risk of disease.

Reproduction

Giant Green Anemones reproduce both sexually and asexually. In the wild, they spawn, releasing eggs and sperm into the water column. Asexually, they can also reproduce through pedal laceration, where small pieces of the base detach and develop into new anemones. In captivity, asexual reproduction is more common, and hobbyists may observe small clones forming around the base of a parent anemone.

Symbiosis

Anthopleura xanthogrammica has a mutualistic relationship with the zooxanthellae algae, which provide the anemone with some of the nutrients it needs through photosynthesis. In return, the anemone offers the algae protection and access to light. While not known for hosting clownfish like tropical anemones, it may associate with various invertebrates, providing them with shelter.

Habitat

This anemone is typically found in rocky intertidal zones and subtidal areas, often attaching itself to rocks or other hard substrates. It can be found from Alaska to Southern California, inhabiting a range of depths, though it is most commonly seen in shallow waters where sunlight is abundant for its symbiotic algae.