Propagating Gold Hammer Coral (Euphyllia ancora)

Fragging guide for the Gold Hammer, a color morph of Euphyllia ancora: branching vs wall fragging, sweeper-tentacle aggression and brown-jelly disease precautions.

Overview

The Gold Hammer is a prized color morph of Euphyllia ancora, a large-polyped stony coral in the family Euphylliidae with golden tentacle tips on a pink or lavender body. Like the base species it carries hammer- or anchor-shaped tentacle tips and is collected primarily from Australia. Colonies grow as branching or wall forms and depend on symbiotic zooxanthellae for most of their energy.

Reproductive Mode

As a morph of Euphyllia ancora, the Gold Hammer shares the same biology: in the wild it is gonochoristic with external fertilization, and new colonies can also form from detached tentacle tips. In aquaria, color morphs are propagated asexually by fragging the colony, since the gold coloration is preserved through cloning rather than spawning.

Fragging / Asexual Propagation

Branching Gold Hammers are the more forgiving form to frag: heads sit on separate skeletal branches and are cut between heads, generally without cutting flesh. Wall Gold Hammers are slower and harder because the colony must be cut through the continuous wall. Each frag should retain a head on its own piece of skeleton before being mounted and allowed to heal.

1. Work with sterile bone cutters or a rotary tool, wearing gloves and eye protection.
2. On branching colonies, separate individual heads at the branch, leaving skeleton beneath each.
3. On wall colonies, plan minimal cuts through the wall to limit tissue damage.
4. Dip and mount the frags, then place them in adequate flow to recover.

Conditions for Propagation

Gold Hammer frags settle under moderate lighting (about 100-150 PAR) and lower-to-moderate flow, with stable alkalinity, calcium, magnesium, and low nutrients. A recovering frag should redevelop a thick flesh band at the skeletal edge and fully extend its tentacles once established.

Sexual Reproduction

Sexual reproduction follows that of Euphyllia ancora: broadcast spawning with external fertilization, documented in Taiwan populations as a synchronized mass spawn on the third and sixth nights after the full moon in late spring. This route is not used by hobbyists, who clone the morph through fragging to keep its color.

Common Challenges

Euphyllia extend long sweeper tentacles tipped with stinging cnidocytes, so Gold Hammer frags need clear spacing from other corals. The leading post-fragging danger is brown jelly disease, which can destroy a colony within weeks and spread to neighbors; reject any piece already coated in a brown gel-like film.