Propagating Frogspawn Coral (Euphyllia divisa)

Fragging guide for frogspawn coral, Euphyllia divisa, distinguishing its wall skeleton from branching relatives and covering sweeper-tentacle and brown-jelly risks.

Overview

Frogspawn coral, Euphyllia divisa, is a large-polyped stony coral of the family Euphylliidae named for its bulbous, multi-tipped tentacles that resemble a clump of frog eggs. It is native to the Indo-Pacific, including Australia, Southeast Asia, the Ryukyu Islands, the Solomon Islands, Fiji, and Palau. A distinguishing feature is its flabello-meandroid wall skeleton, which separates it from the tree-like branching frogspawn relatives.

Reproductive Mode

Like other members of the genus, the coral relies on symbiotic zooxanthellae and reproduces sexually in the wild and asexually by colony division. For the hobbyist, propagation is achieved by fragging, and the wall skeleton makes the species somewhat more demanding to divide than its branching counterparts.

Fragging / Asexual Propagation

Because Euphyllia divisa carries a continuous wall-type corallite skeleton rather than discrete branches, fragging usually means cutting through the wall, which exposes more sensitive tissue than fragging a branching coral. Cuts should be planned to keep each piece with intact polyp tissue and its own skeleton, then dipped and mounted to recover.

Use sterile bone cutters or a rotary tool, with gloves and eye protection.
Plan the cut line through the wall to keep healthy tissue on each piece.
Make as few cuts as possible to limit damage to the sensitive flesh.
Dip and mount the frags, then place them in adequate flow to heal.

Conditions for Propagation

Frogspawn frags recover under moderate lighting and moderate flow, with stable alkalinity, calcium, and magnesium and low nutrients. A healthy frag rebuilds a firm flesh band over the cut edge and inflates its bulbous tentacles fully once it has settled onto the new base.

Sexual Reproduction

Sexual reproduction in Euphyllia is broadcast spawning, with eggs and sperm released into the water for external fertilization, typically synchronized around lunar cues. This wild reproductive route is not practical for hobbyist propagation, so the species is multiplied in the aquarium exclusively by fragging.

Common Challenges

Euphyllia divisa deploys long sweeper tentacles armed with stinging cnidocytes, so frags must be spaced well away from other corals. The most serious post-fragging risk is brown jelly disease, which can kill a colony within weeks and spread to neighbors; never frag or place a specimen already showing a brown gel-like coating.