Hammer corals (Euphyllia ancora) are beloved for their distinctive T-shaped or anchor-shaped tentacles that sway hypnotically in the current. Available in green, gold, purple, and even ultra-colored morphs, they are a centerpiece species in many reef tanks.
Water Parameters
Hammers are more forgiving than SPS but still appreciate stable conditions:
- Temperature: 75–80°F
- Alkalinity: 8–10 dKH
- Calcium: 400–450 ppm
- Nitrate: 5–20 ppm (they can handle moderate nutrients)
Placement
Place hammer corals in the bottom third of your tank in moderate flow. They dislike strong, direct current — it can prevent polyp extension and stress the coral. Indirect, randomized flow is ideal.
Lighting
Medium lighting is best: 50–150 PAR. Under high light, hammers may bleach; under low light, growth stalls and colors fade. A blue-heavy spectrum brings out their fluorescent hues.
Hammer Coral Disease (Brown Jelly)
One risk unique to Euphyllia is brown jelly disease, a bacterial infection that can spread quickly through a colony. Isolate any affected frags immediately and treat with iodine dips. Keep flow adequate to prevent tissue degradation.
Fragging
Hammers can be fragged by cutting between heads with bone cutters. Each head with a skeleton base will regenerate into a full colony. Allow wounds to heal in a separate tank before returning to the display.