After watching my first frogspawn coral refuse to open for two weeks, I learned the hard way that "moderate lighting" means something very specific.
That $60 coral taught me more about patience than any care guide ever could.
If you're struggling with a closed-up frogspawn or worried about getting your first one, you're dealing with the same issues that kill 30-40% of beginner's first attempts.
This guide breaks down exactly what works, including the specific PAR numbers nobody talks about and the 2-3 week timeline that's actually realistic for acclimation.
What is Frogspawn Coral?
Quick Answer: Frogspawn coral (Euphyllia divisa) is a large polyp stony coral known for its distinctive tentacles that resemble frog eggs, making it one of the most popular LPS corals in reef aquariums.
These corals create one of the most mesmerizing displays in any reef tank with their constant gentle swaying motion.
The tentacles really do look like clusters of frog eggs - round tips on long stalks that extend and retract throughout the day.
Scientific Classification Update: Originally classified as Euphyllia divisa, frogspawn coral was recently reclassified to Fimbriaphyllia divisa, though both names are still commonly used in the hobby.
In the wild, frogspawn corals inhabit the Indo-Pacific region, particularly around Australia, Fiji, and the Solomon Islands.
They typically grow at depths of 20-130 feet where they receive filtered sunlight.
You'll find two main growth forms in the hobby:
- Branching variety: Individual heads on separate stalks that can be fragged easily
- Wall variety: Connected tissue forming a continuous wall that's harder to propagate
Color variations range from the common green and brown to rare purple, pink, and orange specimens that command prices of $750-1200 for premium pieces.
Most hobbyists start with standard green varieties at $40-80 per frag.
Essential Frogspawn Coral Care Requirements
Quick Summary: Frogspawn needs stable water parameters (78-80°F, 1.025 sg), moderate lighting (50-150 PAR), gentle indirect flow, and 6-8 inch spacing from other corals.
Water Parameters and Stability
Quick Answer: Frogspawn coral thrives in standard reef parameters with alkalinity at 8-11 dKH, calcium at 400-450 ppm, and magnesium at 1250-1350 ppm.
Stability matters more than hitting exact numbers.
I've seen frogspawn thrive at 7.5 dKH and struggle at a "perfect" 9 dKH when the levels swing daily.
| Parameter | Acceptable Range | Ideal Target | Testing Frequency |
|---|---|---|---|
| Temperature | 76-82°F | 78-80°F | Daily |
| Salinity | 1.024-1.026 | 1.025 | Weekly |
| Alkalinity | 7-12 dKH | 8-11 dKH | 2x Weekly |
| Calcium | 380-450 ppm | 420-440 ppm | Weekly |
| Magnesium | 1200-1400 ppm | 1250-1350 ppm | Weekly |
| Nitrate | 5-20 ppm | 10-15 ppm | Weekly |
| Phosphate | 0.03-0.1 ppm | 0.05-0.08 ppm | Weekly |
Your testing schedule can relax once parameters stay stable for a month.
Monthly supplement costs run $20-40 for an established tank depending on your dosing method.
How Much Light Does Frogspawn Coral Need?
Quick Answer: Frogspawn coral needs moderate lighting between 50-150 PAR, with most specimens thriving at 75-100 PAR in home aquariums.
That vague "moderate lighting" advice causes more frogspawn deaths than anything else.
Here's what actually works:
- Week 1-2: Start at 50 PAR on the sand bed
- Week 3-4: Move to 75 PAR on low rocks
- Week 5+: Final placement at 100-125 PAR
I learned this after bleaching a beautiful green frogspawn by placing it at 200 PAR because my LFS said "they like bright light."
PAR meter investment ($300-600) pays for itself by preventing coral losses.
⚠️ Important: If you don't have a PAR meter, place frogspawn in the bottom third of your tank under LED lights set to 40-50% intensity initially.
For specific LED settings:
- AI Prime/Hydra: 40-50% overall intensity at 12-16 inches
- Radion XR: 35-45% intensity with AB+ spectrum
- Kessil A360: 40-50% intensity, more blue than white
Watch for these visual cues that lighting is correct:
Tentacles extend fully during photoperiod = good lighting.
Tentacles barely visible or tissue looks pale = too much light.
Coral stretching upward with elongated tentacles = needs more light.
Water Flow Requirements
Quick Answer: Frogspawn coral needs gentle to moderate indirect flow that creates a swaying motion without blasting the tissue directly.
Think gentle dance, not headbanging at a metal concert.
The tentacles should sway back and forth rhythmically, never pinned to one side or whipping violently.
Direct flow causes tissue retraction and eventual death - I've seen this happen in less than a week.
Create the right flow pattern:
- Position powerheads: Aim above and around the coral, not at it
- Use rock work: Let rocks deflect and soften flow
- Multiple sources: Two smaller pumps beat one powerful pump
Random flow generators or wave makers work great for creating the varied patterns frogspawn loves.
If you see the flesh pulling back from the skeleton, reduce flow immediately.
Where Should I Place Frogspawn Coral?
Quick Answer: Place frogspawn coral in the bottom to middle third of your tank with 6-8 inches of space from other corals to account for aggressive sweeper tentacles that extend at night.
Those sweeper tentacles can reach 6 inches beyond the normal tentacles and will sting neighboring corals.
I lost a nice torch coral by placing it 4 inches from my frogspawn.
| Placement Factor | Recommendation | Why It Matters |
|---|---|---|
| Height in Tank | Bottom to middle third | Proper PAR levels (50-150) |
| Distance from Others | 6-8 inches minimum | Sweeper tentacle reach |
| Substrate vs Rock | Start on sand, move to rock | Easier acclimation |
| Flow Exposure | Indirect/deflected | Prevents tissue damage |
Safe neighbors include other Euphyllia species (hammers and torches) which can often touch without warfare.
Keep frogspawn far from soft corals, zoanthids, and especially aggressive species like galaxea.
Feeding Your Frogspawn Coral
Quick Answer: While frogspawn coral gets most nutrition from photosynthesis via zooxanthellae, target feeding 1-2 times weekly with meaty foods boosts growth and coloration.
These corals are surprisingly good eaters when settled in.
Feed these foods for best results:
- Mysis shrimp: Defrosted and target fed with a turkey baster
- Reef Roids: Mixed thick and spot fed directly to mouths
- LPS pellets: Fauna Marin or Benepets brands work well
- Chopped seafood: Tiny pieces of shrimp, clam, or fish
Turn off flow for 5-10 minutes during feeding.
Watch the tentacles grab and pull food toward the mouth - it's fascinating.
Overfeeding causes more problems than underfeeding, so start with once weekly and increase if the coral responds well.
Troubleshooting Common Frogspawn Coral Problems
Quick Summary: Most frogspawn problems stem from too much light, wrong flow patterns, or impatience during the 2-3 week acclimation period.
Why Won't My Frogspawn Coral Open?
Quick Answer: New frogspawn corals often stay closed for 1-3 weeks while acclimating to new tank conditions, but prolonged closure indicates issues with lighting, flow, or water chemistry.
Don't panic if your new frogspawn stays closed for the first two weeks - this is normal.
Mine took 18 days to fully extend after purchase.
Follow this diagnostic process:
- Day 1-7 closed: Normal acclimation, don't move it
- Day 8-14 closed: Check parameters, reduce lighting by 25%
- Day 15+ closed: Evaluate flow pattern, test for chemistry issues
- Day 21+ closed: Consider dipping for pests or moving location
Common causes and solutions:
✅ Pro Tip: If tentacles show at night but retract during lights-on, your lighting is definitely too intense.
Check water parameters first - alkalinity swings cause immediate retraction.
Look for hitchhiker pests like flatworms or nudibranchs that irritate the coral at night.
Sometimes moving the coral just 6 inches makes all the difference in flow patterns.
Signs of Healthy vs Unhealthy Frogspawn
Quick Answer: Healthy frogspawn shows fully extended tentacles with vibrant color, while unhealthy specimens display tissue recession, brown jelly, or skeleton exposure.
Learn these visual indicators:
Healthy Signs:
- Tentacles fully extended during day
- Consistent coloration throughout
- Visible feeding response
- New growth at base or tips
- Polyps inflate and deflate naturally
Warning Signs:
- Tissue pulling away from skeleton
- Brown, jelly-like substance on tissue
- Tentacles staying retracted for days
- Pale or bleached appearance
- Skeleton visible through tissue
Act immediately when you see warning signs - coral health deteriorates quickly once problems start.
Brown Jelly Disease and Other Issues
Quick Answer: Brown jelly disease appears as brown, gelatinous slime on coral tissue and requires immediate intervention with dipping and fragging to save unaffected portions.
This disease can kill an entire colony in 48 hours.
Treatment protocol:
- Remove immediately: Take coral out of display tank
- Dip in iodine: 10 drops per cup of tank water for 10 minutes
- Cut affected areas: Frag below any brown jelly infection
- Quarantine: Keep in separate system for observation
Prevention beats treatment - maintain stable parameters and quarantine new arrivals.
Frequently Asked Questions
Are frogspawn corals hard to keep?
Frogspawn corals are considered easy to moderate difficulty, making them perfect for beginners who can maintain stable water parameters. They're more forgiving than SPS corals but need proper lighting and flow to thrive.
Is frogspawn coral aggressive?
Yes, frogspawn coral is aggressive with sweeper tentacles extending up to 6 inches at night to sting nearby corals. Keep them 6-8 inches from non-Euphyllia neighbors to prevent warfare.
How fast does frogspawn coral grow?
Frogspawn coral grows slowly, typically adding 1-2 new heads per year under optimal conditions. Growth rate depends on lighting, feeding, and stable water chemistry.
Can frogspawn touch hammer coral?
Yes, frogspawn and hammer corals can usually touch without fighting since they're both Euphyllia species. Many reefers create beautiful Euphyllia gardens with these corals intermingled.
What should I feed my frogspawn coral?
Feed frogspawn coral mysis shrimp, reef roids, or LPS pellets 1-2 times weekly. Turn off flow during feeding and target feed directly to see tentacles grab the food.
Why is my frogspawn turning brown?
Frogspawn turning brown usually indicates excess nutrients or insufficient lighting causing zooxanthellae overpopulation. Reduce feeding, increase light gradually, and check nitrate/phosphate levels.
Final Thoughts on Frogspawn Coral Care
Success with frogspawn coral comes down to patience during acclimation and getting the basics right.
Remember: stable parameters beat perfect parameters, 50-150 PAR is your target range, and that 2-3 week acclimation period is completely normal.
For those ready to expand their reef knowledge, our comprehensive frogspawn coral guide covers breeding and advanced propagation techniques.