Frogspawn coral is a large-polyp stony (LPS) coral valued for its rounded, branching tentacle tips and movement in the current. It belongs in an established saltwater reef aquarium with stable chemistry, appropriate reef lighting, and room for its tentacles to expand without touching neighbors.
For a first specimen, a healthy aquacultured branching frag is usually a more manageable choice than a large wall colony. Start with the seller’s lighting and water information, then make changes gradually. “Hardy” does not mean tolerant of sudden salinity changes, torn tissue, or an uncycled aquarium.
Branching versus wall frogspawn
The name frogspawn is used for more than one coral. Fimbriaphyllia divisa has a continuous wall-like skeleton, while Fimbriaphyllia paradivisa forms separate skeletal branches. Older labels commonly use Euphyllia. The World Register of Marine Species recognizes Fimbriaphyllia divisa as the accepted name.
This distinction matters for handling and propagation: a separate branch can sometimes be divided through exposed skeleton, whereas cutting a wall colony involves much greater risk to continuous living tissue. Ask the seller which form you are buying and whether the frag has healed.
Practical water and placement targets
| Factor | Starting guidance |
|---|---|
| Temperature | About 76–80°F; keep daily changes small |
| Salinity | About 35 ppt, roughly specific gravity 1.026 at reef temperatures |
| Alkalinity | A stable target around 8–9 dKH |
| Calcium | About 400–450 ppm |
| Magnesium | About 1,250–1,400 ppm |
| pH | Approximately 7.8–8.3; assess daily trends |
| Light | Moderate, with gradual acclimation |
| Flow | Broad, indirect movement; no concentrated jet against flesh |
| Space | Clearance for full expansion, sweepers, and future growth |
These are practical reefkeeping targets, not a prescription to rapidly correct every small deviation. Compare them with your salt mix and supplier’s system. Bulk Reef Supply’s water-testing guidance emphasizes holding a consistent target instead of allowing large fluctuations within a nominally acceptable range.
Test alkalinity often enough to establish consumption, especially after adding stony corals. Dose only from measured demand and the product instructions. Keep a dated log of tests, water changes, and additions so an equipment problem or dosing error can be traced.
Replace evaporation with fresh RO/DI water, not additional saltwater. Use properly mixed saltwater for water changes and verify its salinity before adding it. An automatic top-off system can help maintain water level, but still needs inspection and a safe reservoir arrangement.
Lighting and water movement
Do not place a new frag high under powerful lights simply to make its colors brighter. Ask what light level it came from. If that information is unavailable, a moderate location around 75–150 PAR is a cautious starting range, with observation and gradual adjustment. PAR is measured at the coral; a fixture’s percentage setting is not a transferable light measurement.
Watch for sustained retraction, paling, or tissue damage after a lighting change. None identifies the cause by itself: check water chemistry, flow, and nearby animals too. Tidal Gardens’ frogspawn care guide discusses lighting and circulation.
The tentacles should move rather than remain pinned against the skeleton. Redirect or diffuse a pump outlet if flow is one-sided and forceful. Leave enough circulation to prevent debris collecting around the colony. Our aquarium wavemaker guide explains adjustable circulation options; the highest flow rating is not automatically the best choice.
Placement and coral neighbors
Choose a stable mounting point that keeps living tissue clear of sharp rock edges and prevents the coral from falling. Handle the plug or skeleton rather than squeezing the inflated head. Allow the coral to retract before moving it, and minimize handling.
Leave several inches of open space in every direction initially, then watch tentacle reach after dark and as the coral grows. A fixed gap is not a guarantee: water movement can carry sweeper tentacles toward a neighbor. Increase the distance if any contact occurs.
Do not assume frogspawn, hammer, and torch corals are safe touching because shops group them together. Compatibility varies, and torches can injure neighboring colonies. Clownfish may also irritate or damage a frogspawn by repeatedly pushing into it; the coral is not a substitute anemone that must accept hosting.
Does frogspawn need target feeding?
Photosynthetic symbionts supply much of the coral’s energy. Direct feeding can be optional in a suitably maintained reef; it should not compensate for unsuitable light or poor water quality. Tidal Gardens notes that frogspawn may respond weakly to direct feeding.
If you try feeding, offer a very small amount of fine coral food or suitably small thawed marine food and observe whether it is retained. Do not force large pieces into the mouth or repeatedly feed a retracted, deteriorating colony. Remove uneaten food and stop if feeding increases waste without an obvious response.
Monitor nitrate and phosphate instead of assuming either dirty water or zero nutrients is ideal. Changes to feeding and nutrient export should be gradual and evaluated alongside the whole reef.
Retraction, tissue loss, and brown jelly
Brief retraction can follow disturbance. Persistent collapse, exposed fresh skeleton, receding tissue, or brown disintegrating material warrants prompt investigation. Brown jelly is a descriptive warning sign, not something that can be diagnosed from water quality alone.
- Check temperature, calibrated salinity, alkalinity, and recent dosing or maintenance changes.
- Look for direct pump damage, stinging neighbors, fish picking, and visible pests.
- If tissue is rapidly breaking down, seek experienced coral-health help promptly and isolate the affected colony in a suitable stable reef quarantine system if available.
- Avoid blowing decaying tissue around the display or repeatedly moving the colony between unsuitable containers.
Tidal Gardens’ troubleshooting guide explains aggression, pests, and rapid tissue deterioration. A coral dip is not a universal cure and may not eliminate eggs or all hidden pests. Use only a product suitable for the purpose, follow its label, and do not improvise antibiotic or peroxide doses.
Propagation: what beginners should avoid
Do not cut fleshy polyps with household scissors. Fragging requires knowing exactly where living tissue ends, using appropriate equipment, and working with a healthy colony. Branching frogspawn is generally easier to propagate than wall frogspawn; beginners should seek a demonstration from an experienced coral propagator before attempting either.
Polyp bailout, where living tissue separates from the skeleton, is a stress response—not a recommended reproduction method. Investigate the underlying conditions instead of deliberately trying to trigger it.
Buying and routine care checklist
- Choose a specimen with intact tissue and ask to see it under ordinary lighting as well as blue light.
- Confirm the growth form, healed-frag status, and seller’s husbandry conditions.
- Plan inspection and quarantine before purchase; a quick dip alone does not guarantee a pest-free coral.
- Check expansion, tissue edges, equipment, and water level daily; record chemistry trends on a regular schedule.
- Allow space for growth and reassess neighbors rather than repeatedly relocating an established coral.
A small frag does not define a minimum tank volume by itself. The aquarium must support stable reef conditions and the adult colony’s spacing needs. Frogspawn can be rewarding for a careful newer reefkeeper, but it is not a low-maintenance decoration.