Frogspawn Coral

The frogspawn coral gets its name from its tentacles: each tentacle splits into several short arms, and the arms end in small, round knobs. When the colony is open, these knobs look like a mass of frog spawn. Its skeleton is the same as the hammer coral's; the two species can only be told apart by their tentacle tips. Most colonies sold are the single-piece "wall" type; its branching relative is a separate species (Fimbriaphyllia paradivisa).

With the 2017 molecular revision it was moved from Euphyllia to the genus Fimbriaphyllia; in the hobby it is still called "Euphyllia divisa." Its trade is subject to CITES Appendix II; besides wild-collected colonies, aquacultured frags and maricultured colonies are now easy to find, so choose those.

• Gold frogspawn: Yellow-gold tentacles.
• Green frogspawn: Green body with pale knobs; the most common form.
• Purple tip frogspawn: Cream body with purple or pink knobs.

It lives in the Indian Ocean and Western Pacific in shallow, often turbid reef environments; large colonies are frequently found on vertical surfaces. Colonies can exceed one meter. Living in turbid water shows that it gets part of its nutrition from particles it catches from the water.

• Light: Moderate light, about 75–200 PAR. Make lighting changes gradually; a sudden increase makes the tentacles shrink.
• Flow: Moderate and indirect. The tentacles should sway softly; if they constantly lie in one direction, the flow is too strong.
• Placement: In the middle zone of the rockwork, in a spot with space below and beside it.
• Water parameters: Salinity 1.024–1.026, KH 7–10 dKH, calcium 400–450 mg/L, magnesium 1250–1350 mg/L. Keeping KH and temperature stable matters more than the values themselves. Color and tissue fullness are best with nitrate at 2–10 mg/L and phosphate at 0.03–0.1 mg/L.

The nutrition it gets from its zooxanthellae is its main source, but it is one of the best feeders among the Euphyllia relatives. When given mysis, brine shrimp or finely minced seafood once or twice a week, the tentacles quickly carry the food to the mouth and the colony grows visibly. Feed with the flow turned down; do not let fish snatch food left on the tentacles.

At night it puts out stinging "sweeper" tentacles that can reach 10–15 cm from the skeleton and burns any coral they touch. Leave at least 15 cm of space. In most aquariums it sits next to the hammer coral without problems, but keep it away from the torch coral and other aggressive LPS.

Clownfish often host in frogspawn. Dwarf angelfish, butterflyfish and some hermit crabs may pick at the tentacles; watch it carefully in aquariums with these species.

The wall-type frogspawn is propagated by cutting through the bare skeleton between two heads with a diamond-blade saw. Waiting for the tentacles to retract before starting the cut protects the tissue. The cut pieces are attached to frag plugs with coral glue and rested in low flow. The colony also forms new heads on its own; in large colonies the heads at the edge can over time be cut off as separate pieces.

• Brown jelly: Rapidly spreading, slimy brown tissue. Remove the affected head immediately and give it a coral dip outside the aquarium.
• Rapid tissue recession: Fast tissue loss of not fully understood cause is reported in Euphyllia and its relatives; watch a new colony in quarantine.
• Dull, short tentacles: Too much light, strong flow or very low nutrients are common causes.