Coral care guide
Hammer Coral Care Guide
Hammer corals bring movement and fluorescence to a reef without demanding SPS-level light. They do, however, need stable water, room to expand and flow that moves their polyps without beating them against the skeleton.
At Reef Culture Co., we generally prefer hammer corals over torch corals. After years of growing both, we’ve found hammers noticeably hardier and more forgiving in our systems. That reflects our hands-on experience—not a guarantee that every hammer will tolerate unstable conditions.
Quick care
- Care level: Intermediate
- Lighting: Lower-to-moderate, roughly 50–150 PAR
- Flow: Moderate, indirect and variable
- Placement: Lower-middle to middle reef
- Feeding: Optional occasional target feeding
- Temperament: Aggressive; sweeper tentacles can sting nearby corals
- Best environment: An established, chemically stable reef aquarium
Lighting
Begin in lower light and acclimate gradually. Many hammer corals settle comfortably between approximately 50 and 150 PAR, but polyp extension and coloration should guide the final placement.
Bleaching or persistent retraction can indicate excessive light. Thin, unusually stretched polyps may indicate insufficient light or nutrition. Move slowly—corals generally dislike surprise lighting auditions.
Water flow
Use moderate, indirect and preferably variable flow. The polyps should sway freely while remaining fully inflated. Avoid a direct stream that folds the polyps over or whips the tissue against the skeleton.
A hammer wants movement, not a pressure washer.
Water stability
Consistency matters more than chasing a perfect number. These are Reef Culture Co.’s preferred operating ranges based on the systems where we grow our hammer corals:
- Temperature: 76–79°F
- Salinity: 1.025–1.026 specific gravity
- Alkalinity: 7–8 dKH
- Calcium: 420–450 ppm
- Magnesium: 1,280–1,400 ppm
- Nitrate: 10–20 ppm
- Phosphate: 0.10–0.15 ppm
These are preferences, not universal requirements. Correct parameters gradually; sudden changes in salinity, temperature or alkalinity can cause prolonged retraction and tissue stress.
Placement and spacing
Leave several inches between a hammer and neighboring corals, then observe it after dark. Sweeper tentacles may extend well beyond the daytime colony and damage nearby corals.
Place the skeleton securely so fleshy tissue cannot rub against rockwork. Branching hammers are usually easier to position and propagate than wall-forming colonies, whose continuous tissue can make damage more consequential.
Feeding
Hammer corals receive most of their energy through photosynthesis, but occasional small meaty or planktonic foods may support growth. Feed lightly when the coral is open and responsive, then maintain enough flow to prevent food and debris from collecting between the polyps.
New arrivals
Inspect the flesh and skeleton closely. Begin the coral in lower light with moderate indirect flow and allow it time to settle. Use a quarantine and dipping procedure you already trust; piling several unfamiliar treatments onto a freshly shipped coral can add stress instead of removing it.
Warning signs
Watch for:
- Persistent or worsening polyp retraction
- Tissue pulling away from the skeleton
- Tissue rubbing against sharp skeleton edges
- Brown, gelatinous material
- Sudden inflation loss or polyp bailout
- Nearby corals showing sting damage
Check flow, recent parameter changes, physical damage and neighboring corals first. Rapid tissue loss or brown material should be treated as urgent: isolate the affected coral and avoid sharing contaminated tools or water with healthy Euphyllia.