Species overview
Frogspawn coral typically refers to species in the genus Euphyllia divisa (wall type) and Euphyllia paradivisa (branching type).
Common names: frogspawn coral, octospawn, grape coral, honey coral.
Origin: Indo-Pacific reefs (Australia, SE Asia, Solomon Islands) in moderate current, mid-slope, sometimes turbid waters.
They are large polyp stony (LPS) corals, meaning they build a calcareous skeleton and have fleshy, relatively large polyps.
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2. Ideal water parameters
Keeping parameters stable is key for LPS like frogspawn. Here are target values:
Parameter Typical target
Temperature ~24-28 °C (≈75-82 °F)
Salinity / SG ~1.025 (≈35 ppt)
pH 8.0-8.4
Alkalinity (dKH) ~8-12 dKH
Calcium (Ca) ~350-450 ppm (some suggest 400-480 ppm)
Magnesium (Mg) ~1250-1350 ppm (or ~1300-1400)
Tip: Regular testing and maintaining stability (no large swings) is often more important than hitting a “perfect” number. Several sources note that frogspawn do not tolerate major fluctuations well.
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3. Lighting
Frogspawn do not require extremely intense lighting compared to some SPS corals. Many guides state “moderate” light is best.
Suggested PAR (photosynthetically active radiation) ranges: roughly 50-150 PAR is suitable.
Too much light can cause bleaching or stress; too little light may lead to poor extension, reduced color, or starvation.
Placement: often mid-tank or slightly lower, rather than directly under very high output lights, especially when first introduced.
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4. Water flow
Flow should be moderate: enough to allow the tentacles to gently sway, but not so strong that they are slammed into rock or corners of skeleton.
Flow too strong can damage polyp tissue. Flow too low can lead to stagnation, poor nutrient transfer, or debris accumulation on the coral.
Directional/random but not “blast” flow is preferable — aim for gentle eddies rather than direct high-velocity currents.
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5. Placement & compatibility
Because frogspawn produce sweeper tentacles (long stinging tentacles during the night that can reach and sting neighboring corals), give them space from other corals.
Good placement: on a rock structure, not buried in sand. Many recommend keeping them off the sand bed, because sand movement/irritation can affect them.
Keep them in the middle to bottom of the display depending on lighting/flow – ensure they get light, flow, but aren’t in extremes (too high, too fast).
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6. Feeding & nutrition
Frogspawn get much of their energy from their symbiotic zooxanthellae (photosynthesis) — but direct feeding can boost growth and health.
They are not the most aggressive feeders compared to some LPS, and some hobbyists report mixed success with target feeding.
Typical feeding schedule: a few times a week (e.g., 2-3 times/week) of small meaty foods (e.g., mysis shrimp, brine shrimp, small planktonic food) can help. Some turn off flow briefly during feeding to let the food settle.
Even without frequent feeding they can survive, but growth may be slower.
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7. Common issues & troubleshooting
Issue Possible causes What to do
Polyps retracted / not opening Too strong flow, too much light, stress, new acclimation, poor water chemistry Lower flow, reduce light intensity, check parameters, give time to acclimate.
Bleaching / color fading Excessive light or heat, poor water chemistry, low zooxanthellae Move to more moderate light, check temperature, calcium/alkalinity stable.
Tissue recession / “melting” / polyp bailout Stress condition; flow too high; chemical imbalance; heavy metals; low Ca/alk; sudden change Isolate coral, check/adjust water chemistry, ensure gentle flow, dip coral if needed.
Contact damage / other coral being stung Sweeper tentacles of frogspawn reaching other corals Increase spacing, plug gaps, ensure competitor corals are not too close.
Tip: When introducing a new frogspawn coral, consider a “soft start”: place it in a moderate spot, ensure stability in parameters, gradually acclimate light/flow, and observe for signs of stress.
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8. Propagation (fragging)
Branching types (euphyllia paradivisa) are easier to frag: you can cut at the base of a branch.
Wall types (euphyllia/fimbriaphyllia divisa) are harder and more sensitive.
Always handle with care: the skeleton is sharp; tissue damage increases risk of infection. Use coral-safe tools, dip the frag in coral dip, allow to heal in low stress environment.
After fragging, place in moderate light/flow until healed, then move to your desired location.
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9. Which setups suit frogspawn?
They’re often considered a good choice for intermediate hobbyists (rather than extremely beginner-level) because they are somewhat forgiving but still require stable conditions.
Good in mixed LPS tanks; if you have SPS-dominated, ensure frogspawn are placed where flow and light aren’t extreme.
Avoid placing right next to aggressive coral species (like some SPS that grow fast, or other LPS that extend long sweeper tentacles) unless you plan for spacing.
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10. Summary of key care tips
Maintain stable water chemistry (Ca, alk, Mg, pH, salinity).
Provide moderate lighting (~50-150 PAR) and avoid extremes.
Set up moderate water flow—gentle but enough for movement, avoid blasting.
Ensure proper placement with space around and off the sand.
Feed occasionally for best growth, though not absolutely required.
Monitor for stress signs (retraction, bleaching, tissue loss) and adjust accordingly.
Use caution when fragging and watch for coral aggression.
