Hammer Coral (Euphyllia ancora) Care Guide
An LPS coral with tentacles ending in distinctive T-shaped or anchor-shaped tips. The third member of the popular Euphyllia trio (torch, hammer, frogspawn). Moderate flow and lighting preferred.
Compiled by Aquairi from published sources · Published · Updated
Overview
Euphyllia ancora is a species in the family Euphylliidae. An LPS coral with tentacles ending in distinctive T-shaped or anchor-shaped tips. The third member of the popular Euphyllia trio (torch, hammer, frogspawn). Moderate flow and lighting preferred. Beautiful movement in the current, available in green, gold, and wall varieties.
Taxonomy
- Family: Euphylliidae
- Genus: Euphyllia
- Scientific name: Euphyllia ancora
- Other names: Anchor Coral
- Origin: Indo-Pacific
Habitat
Euphyllia ancora is a large-polyp stony coral of Indo-Pacific reefs whose tentacle tips form a hammer- or anchor-like shape. Powered by symbiotic algae and supplemented by feeding, it extends stinging sweeper tentacles at night and should be kept clear of other corals.
Tank requirements
- Minimum tank volume: 100 L
- Temperature: 24-27 °C
- pH: 8.1-8.4
- Salinity: SG 1.024-1.026
- KH: 8-12 dKH
- Water flow: moderate
- Adult size: 10-25 cm
- Lifespan: 10-30 years
- Difficulty: intermediate
Diet
Classified as omnivore. Recommended feeding frequency: weekly + photosynthetic. In captivity, offer a varied diet appropriate to the species — quality prepared foods supplemented with frozen or live items of suitable size.
Compatibility
- Temperament: semi-aggressive
- Position in tank: bottom
- Compatible tank mates: Clownfish, Wrasses, Gobies
- Avoid with: Nearby Corals, Coral Nippers
Reef compatibility
Generally classified as reef-safe with caution: may disturb other sessile invertebrates, sting neighbouring corals or prey on small ornamental shrimps, so placement and tankmates need consideration.
Propagating Hammer Coral (Euphyllia ancora)
Overview
Hammer coral, Euphyllia ancora, is a large-polyped stony coral of the family Euphylliidae, recognizable by the hammer- or anchor-shaped (T-shaped) tips on its tentacles. It occurs through the tropical Indo-West Pacific from the Maldives to the Solomon Islands, with large populations in Indonesia. Colonies form either flabello-meandroid (wall) or phaceloid/branching structures, and they host symbiotic zooxanthellae acquired during larval development.
Reproductive Mode
In nature the species is gonochoristic and reproduces by external fertilization, while new colonies can also form from detached tentacle tips. In the aquarium, propagation relies on asexual division of the colony, and the difficulty depends heavily on whether the colony grows as a branching head cluster or as a solid wall.
Fragging / Asexual Propagation
Branching hammers are the easier morph to frag: individual heads sit on separate skeletal branches and can be cut between heads, usually without slicing through flesh. Wall hammers are slower-growing and harder to frag because dividing the colony means cutting through the continuous wall and its sensitive tissue. Cut each head with its own piece of skeleton and allow it to recover.
- Use sterile bone cutters or a rotary tool, with gloves and eye protection.
- On branching colonies, cut between heads along the skeletal branch, keeping skeleton under each head.
- On wall colonies, expect to cut through the wall and minimize the number of cuts.
- Dip the frags, mount them, and place in adequate flow to heal.
Conditions for Propagation
Hammer corals recover under moderate (about 100-150 PAR) lighting and lower-to-moderate flow, with stable alkalinity, calcium, and magnesium and low nutrients. A healthy frag shows a thick flesh band around the skeletal edge and fully extended, well-defined tentacles once settled.
Sexual Reproduction
Sexual reproduction in Euphyllia ancora is broadcast spawning: in Taiwan populations a mass spawn occurs in late spring, synchronously on the third and sixth nights after the full moon during neap tides. Captive sexual reproduction is not a practical propagation route for hobbyists, who rely on fragging instead.
Common Challenges
Euphyllia deploy long sweeper tentacles armed with stinging cnidocytes, so frags must be spaced away from other corals they could reach and sting. The most serious post-fragging threat is brown jelly disease, which can kill an affected colony within weeks and spread to others; avoid specimens already showing a brown gel-like coating.