Hammer Coral

Environment

Mature reef aquarium of 200 liters minimum. Medium to high lighting (PAR 100-200), with shaded areas available for gradual acclimation. Moderate flow (indirect and random) to gently sway the tentacles without damaging them. Parameters: salinity 1.024-1.026, KH 7-10 dKH, calcium 400-450 mg/L, magnesium 1250-1350 mg/L, nitrates <10 mg/L, phosphates 0.03-0.08 mg/L. Stable temperature 24-26°C. Placement on stable substrate, middle zone of the tank, with 15-20 cm safety space around (extensible stinging tentacles at night).

Feeding

Symbiotic zooxanthellae provide 70-80% of energy needs through photosynthesis. Supplemental feeding 2-3 times/week: brine shrimp, mysis, chopped krill, mussel or shrimp meat (3-5 mm pieces). Feed in the evening when tentacles are extended, directly on the polyps. Avoid overfeeding which pollutes the water. Well-fed specimens show better growth and coloration.

Health & common diseases

Euphyllia are susceptible to tissue recession syndrome (RTN/STN) often caused by sudden parameter fluctuations or stress. Symptoms include excessive polyp retraction, mucus loss, and progressive tissue necrosis starting from the base or extremities. Prevention involves slow acclimation, stable parameters (calcium 400-450 mg/L, KH 8-10, magnesium 1250-1350 mg/L), moderate indirect flow, and avoiding contact with other corals or stinging organisms. Also watch for secondary bacterial infections and predatory flatworm infestations.

Tips & tankmates

Progressive light acclimation essential (start at bottom of tank, raise over 2-3 weeks). Very stinging tentacles: wear gloves, maintain distances from other corals. Semi-aggressive: deploys sweeper tentacles up to 20 cm at night. Sensitive to sudden parameter changes and stress (handling). Monitor prolonged retraction (sign of stress, parasites, or poor water quality). CITES Appendix II species: certificate required for international trade. Prefer aquacultured specimens (frags) that are more robust and ethical. Compatible with peaceful fish; beware of angelfish, butterflyfish, and certain blennies that may nip at tissues.

Sources

• Coral Magazine - Euphyllia Care Guide
• ReefBuilders - LPS Coral Maintenance
• CITES Appendices