Coral guide
Green Star Polyp
Pachyclavularia violacea (often sold under older or alternate trade identifications)
Green Star Polyp is an encrusting soft coral with fast to very fast growth after acclimation. Its main long-term management challenge is containing the mat and pruning it before it reaches neighboring corals, pumps, overflows, seams, or porous rock.
Quick Reference
- Care difficulty
- Beginner-friendly: Yes
- Coral type
- Encrusting soft coral (octocoral)
- Growth rate
- Fast to very fast after acclimation
- Lighting
- Low to moderate for most colonies
- PAR
- Approximately 50-150 PAR; 75-125 PAR is a practical starting range for many systems
- Flow
- Moderate to strong indirect flow
- Temperature
- 75-80°F (24-27°C)
- Salinity
- 1.024-1.026 specific gravity (about 32-35 ppt)
- pH
- 8.1-8.4
- Alkalinity
- 8-11 dKH; consistency is more important than a specific target
- Calcium
- 400-450 ppm
- Magnesium
- 1250-1400 ppm
- Spacing
- At least 3-6 inches plus a physical gap
- Reef safe
- Compatible with most reef-safe fish when isolated and pruned
Key Takeaways
- Difficulty: Use an isolated rock, separate island, or aquarium back wall.
- Lighting: Leave a true physical gap because the mat can cross connected rock.
- Beginner friendly: Wear waterproof gloves and eye protection when fragging or handling cut tissue.
Habitat and placement
Green Star Polyp occurs in shallow reef flats, lagoons, rubble areas, and reef slopes where the mat can encrust exposed hard substrate. Place it on a removable isolated rock, separate island, or back wall, with a true physical gap from the main reef structure and neighboring corals.
Attach the frag plug or mat-bearing rubble to solid rock, a frag plug, or clean aquarium glass. Sand alone will not permanently contain a mat that reaches nearby rock.
Lighting, flow, and parameters
Low to moderate light suits most colonies, and brighter reef lighting requires gradual acclimation. Moderate to strong indirect flow keeps the mat clean; random, turbulent, or alternating flow is preferred to a narrow pump jet.
Supplied reef parameters are 75-80°F (24-27°C), 1.024-1.026 specific gravity (about 32-35 ppt), pH 8.1-8.4, alkalinity 8-11 dKH, calcium 400-450 ppm, magnesium 1250-1400 ppm, nitrate approximately 2-15 ppm, and phosphate approximately 0.03-0.10 ppm. Ammonia and nitrite should remain at 0 ppm.
Growth and aggression
The purple mat advances over adjacent hard surfaces and can cover rock structures, aquarium walls, overflow boxes, and equipment if not pruned. It can smother slower corals, cover coral bases, enter crevices, and become difficult to remove from porous rock.
Its competitive potential is high because of rapid overgrowth. Keep it at least 3-6 inches from other corals plus a physical gap; distance alone is temporary if the mat can reach connected rock.
Nutrition and propagation
Green Star Polyp is photosynthetic. Target feeding is not required; fine food may be broadcast occasionally, while direct heavy feeding can foul the mat and water.
Propagation is mechanically easy, but gloves, eye protection, and clean tools are recommended. Cut or peel a section of healthy mat, preferably with a thin piece of underlying rock, and attach it to new substrate.
Health and safety
Brief closure is normal after disturbance or during shedding. Persistent closure can indicate flow, light, parameter, pest, algae, or irritation problems. Common problems include tissue recession, bleaching, algae, localized mat decay, and weak attachment.
Wear waterproof gloves and eye protection, cover cuts, prevent splashes, wash hands and tools, and keep fragments away from drains, children, and pets. Normal coral-handling precautions still apply.
Frequently Asked Questions
Why have my Green Star Polyps stopped opening?
Check for a recent lighting or flow change, unstable salinity or temperature, alkalinity or nutrient swings, sediment or algae on the mat, nearby stingers, and pests. Colonies may close briefly after maintenance or while shedding, but progressive tissue loss or closure lasting many days needs investigation.
Sources and Further Reading
- World Register of Marine Species WoRMS Editorial Board
- What is Zooxanthellae? NOAA National Ocean Service