Hammer Coral Care Guide
Hammer corals are one of the most popular large-polyp stony (LPS) corals. Their flowing, anchor-shaped tentacles add constant movement to a reef tank, and they're a great first step into LPS.
Branching vs. wall hammers
Branching hammers grow as separate heads on individual stalks, which makes them easy to frag. Wall hammers grow as one continuous, wall-like skeleton. Both share the same care needs.
Lighting
Hammers prefer moderate light, roughly 75 to 150 PAR. Too much light can make them retract and lose color. Start a new hammer in the lower to middle part of the tank and move it up gradually if needed.
Flow
Aim for moderate, indirect flow that makes the tentacles sway gently. Strong direct flow can tear the soft tissue and keep the coral from fully extending.
Spacing and sweeper tentacles
Hammers extend long sweeper tentacles, especially at night, that sting nearby corals. Give them at least 6 inches of space from other corals. Most hammers can touch other hammers without harm, but keep them apart from other Euphyllia species like torches until you see how they react.
Water parameters
As stony corals, hammers build skeleton from calcium and alkalinity. Keep alkalinity steady between 7 and 11 dKH and calcium around 400 to 450 ppm. Sudden alkalinity swings are a common cause of tissue recession.
Feeding
Hammers get most of their energy from light. Occasional feeding with small foods like reef roe or mysis can boost growth. Feed gently, and only when the tentacles are extended. Browse our fish and coral food.
Warning signs
- Tissue receding from the skeleton: often linked to alkalinity swings or stinging from neighbors.
- Brown jelly: a brown, slimy film on the tissue that can spread fast. Remove the affected head right away and dip the coral.
- Euphyllia-eating flatworms: small, flat pests on the tissue. Dip every new hammer before adding it to your tank.
New to dipping? Read our Coral Acclimation & Dipping Guide.
Browse our hammer coral collection.
