Hammer coral (Euphyllia ancora) care guide

Group
Corals
Other names
Fimbriaphyllia ancora, Anchor coral, Branching hammer coral, Wall hammer coral
Family
Euphylliidae
Origin
Indo-Pacific, from the Indian Ocean to the western Pacific; Indonesia and Australia supply most specimens
Water
saltwater
Temperature
22–26°C
pH
8.1–8.4
Hardness
dKH 8–12
Care level
intermediate
Reef safe
with_caution
Lighting
Moderate; about PAR 80–150
Flow
Moderate, indirect

Care

Hammer coral is a large-polyp stony (LPS) coral whose fleshy polyps end in hammer- or anchor-shaped tips, and they stay out day and night. Colours are green, tan or brown with lime, yellow, pink or purple tips, and metallic green and gold forms are popular. It grows as a wall or as a branching colony. Place it low to mid tank on stable rock. LiveAquaria lists it as moderate in care, with moderate light and medium flow; Top Shelf suggests PAR 80–150, raised over 1–2 weeks, and gentle to moderate indirect flow that moves the polyps without whipping them. Strong direct flow can tear the tissue. Water: LiveAquaria gives dKH 8–12, pH 8.1–8.4 and 22–26 °C, with calcium, strontium and trace elements. Top Shelf suggests calcium 400–450 ppm and magnesium about 1300–1400 ppm. Growth is moderate. Watch for receding tissue or brown jelly, and avoid sudden changes. Naming: in 2017 hammer and frogspawn corals were moved from Euphyllia to the genus Fimbriaphyllia, so this species is now Fimbriaphyllia ancora. Aquacultured colonies are sold as well as wild ones. Selling: this is a CITES Appendix II coral. Frags grown in the UK can be sold freely; wild-collected or imported pieces must have been legally imported with CITES paperwork. Sources: LiveAquaria (liveaquaria.com/products/hammer-coral-1); Top Shelf Aquatics (topshelfaquatics.com/pages/corals/green-hammer-coral). Checked October 2026.

Diet

Mainly photosynthetic, but it benefits from small meaty foods once or twice a week when the tentacles are out: mysis, brine shrimp, finely chopped shrimp or clam, or coral powders.

Breeding

Branching colonies are easy to frag: cut between heads at the skeleton with bone cutters or a saw, glue the head to a plug and keep it in low flow while it heals. Wall forms need a saw. Cut the skeleton, not the tissue, and handle it by the skeleton.

Compatibility and tank mates

Aggressive. At night its sweeper tentacles can reach about 15 cm, so leave at least 15 cm around it. Other Euphyllia and Fimbriaphyllia usually tolerate each other better. Clownfish may host in it but persistent hosting can irritate it. Avoid coral-nipping angelfish.

Last updated 8 October 2026. Community-edited care guide on Aquatic-Auctions.

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