Description
Palythoa grandis – Palythoa grandis
Palythoa grandis, often referred to simply as the Grandis Paly, is one of the largest and most impressive colonial zoanthids in the reefing world. Each polyp can reach up to 5 cm (2 inches) in diameter, creating a bold, flower-like display that adds striking presence to the aquarium. Known for its dramatic size and earthy, metallic coloration—ranging from olive green and bronze to golden and orange—P. grandis provides a natural, organic aesthetic that contrasts beautifully with smaller Zoanthus species. Under actinic and blue-spectrum lighting, its oral disc and tentacle edges glow vividly, highlighting subtle color transitions and texture.
Lighting: Moderate (80–150 PAR); develops optimal color and expansion under blue-dominant LED or hybrid T5/LED systems
Flow: Moderate; prefers gentle, variable flow that allows full polyp extension while preventing detritus accumulation around the base
Placement: Bottom to mid-level on rock or rubble; allow room for colony expansion and avoid shaded or stagnant areas
Temperature: 76–80°F (24–27°C)
Salinity: 1.024–1.026 SG
pH: 8.1–8.4
Alkalinity: 8–10 dKH
Calcium: 400–440 ppm
Magnesium: 1250–1350 ppm
Nutrients: Moderate (NO₃ 5–15 ppm, PO₄ 0.05–0.10 ppm); slightly nutrient-rich water enhances color depth and polyp expansion
Feeding: Photosynthetic but benefits from occasional target feeding with fine meaty foods or coral blends to accelerate growth and intensify pigmentation
Aggression: Low to moderate; non-stinging but can crowd neighboring corals over time—monitor spreading colonies
Growth Rate: Moderate; expands steadily through budding and mat formation under stable conditions
Care Level: Easy – highly adaptable and tolerant, suitable for both novice and experienced reef keepers
Compatibility: Peaceful; ideal for soft coral and mixed reefs, pairing well with Zoanthus, mushrooms, and leathers
Note: Like all Palythoa species, P. grandis may contain palytoxin—a potent natural defense compound. Handle with care using gloves and protective eyewear when fragging or cleaning to prevent exposure.
