Description
Galaxea – Galaxea fascicularis
Galaxea fascicularis, commonly known as the Galaxea, is a classic large-polyp stony (LPS) coral admired for its vibrant coloration, dynamic polyp structure, and distinctive fluorescence. Each colony forms dense clusters of elongated corallites with brilliant green, gold, or purple tissue and contrasting tips that glow intensely under blue-spectrum lighting. When extended, its sweeping tentacles create a shimmering field of movement that adds both texture and energy to the reef display. Though stunning, Galaxea is also known for its formidable sweeper tentacles, making spacing and placement critical in mixed coral environments.
Lighting: Moderate (100–180 PAR); best color and polyp extension achieved under blue-heavy LED or hybrid T5/LED systems
Flow: Moderate to strong; enjoys alternating, turbulent flow that keeps the polyps gently extended and prevents detritus buildup
Placement: Bottom to mid-level on stable rockwork with at least 20 cm of open space around the colony to accommodate long sweeper tentacles
Temperature: 76–80°F (24–27°C)
Salinity: 1.024–1.026 SG
pH: 8.1–8.4
Alkalinity: 8–10 dKH
Calcium: 420–450 ppm
Magnesium: 1300–1400 ppm
Nutrients: Moderate (NO₃ 5–15 ppm, PO₄ 0.05–0.10 ppm); stable nutrient balance maintains tissue vibrancy and prevents fading
Feeding: Photosynthetic but benefits from weekly feedings with fine meaty foods or reef roids to encourage tissue growth and polyp expansion
Aggression: Very high; extends long, potent sweeper tentacles capable of stinging corals over 15–20 cm away—space accordingly
Growth Rate: Moderate; forms dense, branching colonies that can spread quickly under favorable conditions
Care Level: Intermediate – hardy but requires careful placement to prevent aggression toward neighboring corals
Compatibility: Aggressive; best suited for LPS-dominated or species-specific zones with adequate space and flow
