Common name: Octopus coral

General information

Galaxea astreata, commonly known as Galaxea Coral or Galaxy Coral, is a species of large polyp stony (LPS) coral that is popular among reef aquarium enthusiasts for its striking appearance. It is characterized by its long, sweeper tentacles that can extend several inches from its body, especially at night. These tentacles are tipped with potent nematocysts (stinging cells) that the coral uses for defense and to capture prey.

The coloration of Galaxea astreata can vary widely, with hues ranging from green to brown, and sometimes with fluorescent tips. This coral is known for its rapid growth rate under optimal conditions and can form large, dome-shaped colonies over time.

Care

Galaxea astreata requires moderate to high lighting and moderate water flow in the aquarium. It is important to provide ample space between it and other corals to avoid damage from its long sweeper tentacles. This coral benefits from supplemental feedings of microplankton or finely minced seafood to support its growth and health.

Calcium, alkalinity, and magnesium levels should be maintained within appropriate ranges to support the coral's skeletal growth. Regular water changes and stable water parameters are crucial for the well-being of Galaxea astreata.

Symbiosis

While Galaxea astreata does not have any specific symbiotic relationships akin to clownfish and anemones, its extended sweeper tentacles can help to keep the surrounding area free from other encroaching corals, indirectly benefiting its immediate neighbors by reducing competition for space and resources.

Habitat

Galaxea astreata is found in the Indo-Pacific region, typically in shallow reef environments. It prefers areas with strong lighting and some water movement, which are conditions that can be replicated in the home aquarium to promote its health and growth.