Galaxy Coral Care Guide
Galaxy Coral (Galaxea fascicularis) is a LPS coral. Care covers 75-175 PAR, medium flow, reef parameters and feeding; intermediate level.
Compiled by Aquairi from published sources · Published · Updated
Overview
Galaxy Coral (Galaxea fascicularis) is a LPS coral in the family Euphylliidae. Spectacular LPS with star-burst polyps and very long, very aggressive sweeper tentacles. Place isolated to avoid burning neighbors.
Taxonomy
- Family: Euphylliidae
- Genus: Galaxea
- Scientific name: Galaxea fascicularis
- Common synonyms: Crystal Coral, Star Coral
Habitat
In the wild, Galaxea fascicularis is reported from Indo-Pacific, where it occupies mid to lower reef slopes and lagoons (typically 5-30 m). The species adopts a branching growth form on hard substrate within zooxanthellate reef communities.
Tank requirements
- Salinity (specific gravity): 1.024-1.026
- Temperature: 24-26 °C (75-79 °F)
- pH: 8.1-8.4
- Carbonate hardness (dKH): 8-11
- Calcium: 400-450 ppm
- Magnesium: 1280-1350 ppm
- Phosphate (max): 0.03 ppm
- Nitrate (max): 5 ppm
- Minimum system age: 6 months
Placement and lighting
- PAR (placement zone): 75-175 PAR
- Water flow: medium
Mount this LPS coral on the lower or mid rockwork or on the sand bed (for free-living forms) where light is moderate. Strong direct flow can damage the fleshy tissue; aim for indirect, varied movement.
Feeding
Galaxea fascicularis hosts symbiotic zooxanthellae and derives most of its energy through photosynthesis. Supplemental target feeding accelerates growth and supports colouration; commonly accepted items include mysis, reef-roids. Feed once or twice per week after lights-out, when polyps are extended.
Compatibility
This coral is very-aggressive toward neighbours. It extends sweeper tentacles capable of stinging adjacent corals, so leave generous spacing (10-20 cm) between colonies. Reef-safe with most fish and invertebrates.
Care notes
Difficulty level: intermediate. Reported skeletal growth in well-tuned reef tanks is approximately 0.2-0.5 cm/month. Propagation by fragmentation is straightforward for branching colonies — separate branches or polyps with a bone cutter, glue to plug, allow 1-2 weeks for healing. Maintain stable alkalinity (avoid swings above ±0.5 dKH per day) to preserve tissue health.
Galaxea fascicularis Propagation Guide
Overview
Galaxea fascicularis, the galaxy or star coral, is a large-polyp stony coral in the family Euphylliidae. Its skeleton bears circular, tube-shaped corallites less than 1 centimetre across, with ridge-like septa radiating from the centre. Colonies begin as low domes and become more irregular, massively hummocky or columnar with age.
Reproductive Mode
Galaxea fascicularis reproduces both sexually and asexually. Sexually, sperm and eggs are released into the water in synchronized spawnings for external fertilisation, and the resulting planula larvae drift before settling and undergoing metamorphosis. Asexual increase of the colony occurs by budding.
Fragging / Asexual Propagation
In the aquarium, this coral is propagated by cutting the skeleton between clusters of corallites so each fragment carries one or more intact, living corallites. A coral saw gives the cleanest division. As with other stony corals, retaining living polyp tissue on the frag is what allows it to regrow.
- Identify a section with several healthy corallites.
- Cut the skeleton between corallite clusters with a coral saw.
- Mount each frag so its living corallites face the light.
- Dip the frag to reduce infection risk while it heals.
Conditions for Propagation
Frags recover in stable reef conditions with medium light and flow. Galaxea also feeds heterotrophically on organic particles and zooplankton, so periodic feeding supports the energy demand of healing tissue.
Common Challenges
Galaxea is a notorious aggressor. Its sweeper tentacles can extend up to 30 centimetres (about 12 inches) and serve to deter other organisms from settling nearby. Even small frags must be given a wide isolation zone, because the sweepers reach well beyond the visible colony outline.