Are you interested in keeping the Frogspawn coral in a saltwater aquarium, but aren’t sure if it is hard to keep, where to put it, or how quickly it will even grow? Let’s dive right into some tips about Frogspawn coral care, and answer some of your questions.
Table of contents:
Frogspawn coral care
The key to successful Frogspawn coral care in a saltwater aquarium is to provide the coral with aquarium conditions that will help it thrive. There are three key areas to focus your efforts:
- Water chemistry
- Proper placement to provide sufficient water flow and light
- Feeding
Water chemistry needed for Frogspawn coral care
In order to provide adequate Frogspawn coral care, you have to create and maintain stable reef tank water parameters. The short version here is that you need to maintain a stable:
- Temperature: 78-82 degrees Fahrenheit (25.5-27.8 C)
- pH: 8.2
- Alkalinity: 8-12 dKH
- Calcium: 400 ppm
- Salinity (measured as specific gravity): 1.025
- Ammonia, nitrates, and nitrites: 0
Why do these parameters matter?
- Temperature: Frogspawn corals rely on stable temperatures for metabolic processes. Temperatures outside the recommended range can stress the coral, leading to polyp retraction, slowed growth, or even tissue loss. Rapid swings are especially harmful and can trigger bleaching.
- pH: A stable pH around 8.2 supports healthy calcification and zooxanthellae function. Fluctuations or low pH can impair skeletal growth and stress the coral.
- Alkalinity: Alkalinity (8-12 dKH) buffers the water against pH swings and is essential for skeletal formation. Low alkalinity can cause tissue recession and poor growth; high alkalinity can lead to precipitation and instability.
- Calcium: Calcium (around 400 ppm) is a building block for the coral’s skeleton. Deficiency leads to slow or halted skeletal growth, while excess can cause precipitation and imbalance.
- Salinity: Frogspawn corals are sensitive to changes in salinity. A specific gravity of 1.025 mimics natural reef conditions. Sudden changes can cause osmotic stress, polyp retraction, and tissue damage.
- Ammonia, nitrites, and nitrates: These should be as close to zero as possible. Ammonia and nitrite are toxic even at low levels, causing rapid tissue loss or death. Nitrate should be kept low; elevated nitrate can cause browning, poor polyp extension, and increased susceptibility to disease.
Stability is more important than chasing exact numbers. Rapid parameter swings—such as a sudden drop in alkalinity or a spike in temperature—are common causes of polyp retraction, tissue loss, or brown jelly infections. Use a reliable test kit and log your results. If you notice your Frogspawn coral retracting or showing tissue recession, check for recent parameter changes first.
Proper placement for Frogspawn coral care provides sufficient water flow and light
In the ocean, water currents, waves, and tides bring oxygen, food, and nutrients to all coral types, while sweeping away waste. The sun provides the perfect light to sustain growth. In a saltwater aquarium, we have to recreate those conditions. Aquarium pumps and powerheads are used to create life-sustaining water flow and LED lights are generally used to replace the sun.
The Frogspawn coral isn’t able to move itself to the best location in your tank, you have to pick the location for it, and the ideal placement is going to be different, from one aquarium to another. The key is to think like Goldilocks–not the breaking-and-entering part, but the part about not providing too much or too little of a good thing.
Water flow
The ideal Frogspawn coral placement is going to have moderate water flow–too much flow and the coral polyps will retract (and might get damaged or tear). Too little flow won’t provide enough oxygen for strong growth.
- Signs of too much flow: Polyps remain tightly retracted, tissue appears to flap or tear, or the coral leans away from the current. You may see exposed skeleton or tissue damage at the base.
- Signs of too little flow: Polyps may extend but appear limp, detritus accumulates on the tissue, and the coral may develop brown or slimy patches due to poor waste removal.
Moderate, indirect flow is best—enough to gently sway the polyps without blasting them. Observe the coral: healthy polyps should be extended and gently moving, not whipping or collapsing.
Light
Proper Frogspawn coral care requires you to provide moderate light. They will bleach under intense lighting and will starve under low levels of lighting.
- Signs of too much light: Bleaching (loss of color), tissue recession, or failure to expand. The coral may appear pale or white as it expels its zooxanthellae.
- Signs of too little light: Browning, lack of growth, or poor polyp extension. The coral may become dull and sluggish over time.
The biological basis: Frogspawn corals host zooxanthellae, which require light for photosynthesis. Too much light damages these symbionts; too little starves the coral. Adjust placement and light intensity based on these cues, and make changes gradually to avoid shock.
Practical placement tips
If you have strong reef lighting, the best placement is typically towards the bottom of the tank, on or near the substrate, and off to the side or outer perimeter of the aquarium light. If you have a small nano aquarium with relatively weak LED lights, you may need the coral to be closer to the middle, to receive adequate light. And as mentioned before, that same area should have moderate flow, provided by a gyre pump or a powerhead.
A final thought on placement
Another important element of the ideal coral placement is to ensure adequate space between your Frogspawn coral and other corals in the aquarium.
Sweeping stings
Sweeper tentacles are an issue with the Frogspawn coral. It is a relatively aggressive coral and the sweeper tentacles pack a sting and will damage nearby corals.
Understanding coral aggression: Frogspawn corals deploy sweeper tentacles—long, stinging extensions—especially at night or when sensing nearby competitors. These tentacles deliver nematocyst stings to neighboring corals, causing tissue necrosis or recession at contact points. Early warning signs of aggression include tissue loss or pale, dying tissue where corals touch or are close together. Over time, this can lead to permanent damage or loss of neighboring colonies.
Sweeper tentacles can get along with this species, so it is best to give the frogspawn coral a wide berth–like 6 inches on every side–to be safe. If you cheat and try to stack other corals too close to the Frogspawn coral, you will regret it, because the coral will simply burn its way into the aquascape.
The biggest challenge with caring for the frogspawn coral–Euphyllia divisa–is the 6-inches rule
That reminds me of a game we played as kids. Did anyone else play a barbaric game as a kid called 6-inches?
If you want to properly care for this and other corals, you should place all other corals at least 6 inches away from the Frogspawn at any given time…that means when you newly place the frag in your tank…one year down the road and 3 years down the road, too, when all the corals are growing together. Yikes.
The one exception to this rule is with other similar Euphyllia species, like the anchor and torch corals, which should not be damaged by the sweeper tentacle of a neighboring colony. This is because closely related Euphyllia species often have some degree of chemical compatibility, reducing the risk of aggression. So if you can at all manage it, try to put other similar species nearby. Here’s a tip I picked up in Borneman’s book, Aquarium Corals:
To keep the formation of sweeper tentacles down, avoid placing these corals in a spot with exceptionally fast water flow.
When planning your aquascape, anticipate future growth—Frogspawn colonies can expand significantly over time, so leave extra space for their eventual size, not just their current footprint.
Acclimation
Acclimation is going to be key. Even if you have the perfect place for your new coral, it might not be perfect right away. If there is significantly more or less intense lighting or dramatically more or less water flow, the change might stress your coral. Too much stress and the coral could bleach and die, or just die. So it is typically best to scale back your aquarium lights and gradually increase the intensity to help your coral better acclimate to the conditions in your saltwater aquarium.
Why gradual acclimation matters: Sudden changes in light or flow can shock the coral’s tissues and its symbiotic zooxanthellae, leading to bleaching (expulsion of zooxanthellae), tissue loss, or polyp retraction. Frogspawn corals are particularly sensitive to abrupt environmental changes.
Stepwise acclimation protocol:
- Dim your aquarium lights or use a shading screen to reduce intensity for the first few days.
- Gradually increase light intensity or photoperiod over 1-2 weeks, monitoring the coral’s response.
- Introduce moderate flow, but avoid direct blasts. Adjust as needed based on polyp extension.
- Observe for signs of stress: retracted polyps, pale or bleached tissue, or failure to expand. If these occur, slow the acclimation process or reduce intensity further.
If acclimation fails and the coral shows persistent stress, consider moving it to a lower light or lower flow area and repeat the gradual increase.
Feeding
The Frogspawn coral, like all corals, is an animal–and animals need to eat. That can be confusing, sometimes, when thinking about corals, because we buy expensive aquarium lights, to provide an energy source for them.
But the corals are not plants, they are animals, that ‘house’ tiny organisms called zooxanthellae. These zooxanthellae are the creatures that harness the light power to make sugars–and they do provide a fair amount of the nutrition for the coral, but it is still generally best for you to feed your frogspawn, in addition to providing it with adequate light.
The technique used generally is called ‘spot feeding’. That’s where you take a device like the Sea Squirt or Julian’s Thing and drop some small, meaty foods on the polyps. The key or the ‘trick’ here is to match the food particle size with what the coral wants to eat, which takes some trial and error sometimes.
There are also hobbyists who report success feeding tiny pellets, although I have not personally had success with this.
Feeding frequency and trade-offs: Regular spot feeding (1-2 times per week) can promote faster growth, improved coloration, and polyp extension. However, overfeeding can lead to nutrient spikes, increased nitrates, and algae blooms, which harm both the coral and the tank. If your tank already has elevated nutrients, reduce feeding frequency or skip feeding altogether.
Signs your Frogspawn is benefiting from feeding: Increased polyp extension during feeding, visible growth, and robust coloration. If the coral ignores food or retracts, reduce feeding frequency.
Practical tip: Start with small amounts and observe water quality. Adjust feeding based on coral response and tank nutrient levels.
Are Frogspawn corals hard to keep?
Frogspawn corals are hardy and attractive LPS species that are relatively easy to care for, by coral standards, if the proper aquarium conditions are provided for.
Varieties of Frogspawn coral
There are actually two different species of Frogspawn coral that are somewhat commonly kept in the saltwater aquarium hobby. The most common species has the scientific name Euphyllia paradivisa. Euphyllia is the genus that contains Hammer corals and Torch corals, and the other species of Frogspawn coral, named Euphyllia divisa.
Key differences between E. paradivisa and E. divisa:
- Growth form: E. paradivisa grows as clusters of small, thin branches (like a coral bouquet), making it easier to frag and propagate. E. divisa grows as a single-walled, fleshy coral with no branching, making fragging more difficult and risky.
- Fragging: E. paradivisa is easier to frag by cutting branches, while E. divisa requires careful sawing of the wall, increasing the risk of tissue damage.
- Placement: Both species require similar care, but E. divisa’s larger, continuous tissue sheet makes it more sensitive to physical damage and aggression from neighbors.
- Compatibility: Both can be placed near other Euphyllia species (hammer, torch), but always observe for signs of aggression.
Common confusion: Frogspawn corals are sometimes mislabeled as hammer or torch corals due to similar polyp shapes and colors. Accurate identification is important for proper care, fragging, and placement, as torch corals (E. glabrescens) are generally more aggressive and have longer sweeper tentacles.
You will find that certain local fish stores or online stores may also categorize them by their color: blue or green, for example. The more exotic the color morph, the more expensive the coral is, generally speaking, although coloration is also influenced by the lighting spectrum used.
Problems encountered during Frogspawn coral care
As mentioned earlier, the Frogspawn coral is a hardy LPS species. They don’t tend to have a lot of problems in the home aquarium. The biggest issues to prepare for in Frogspawn coral care :
- Aggression between coral species
- Polyps being nipped by a not-so-reef-safe saltwater fish
- Polyps not opening-up
- Physical damage due to handling
- Brown jelly infections
- Bleaching
Troubleshooting Frogspawn coral problems:
- Check water chemistry: Test temperature, pH, alkalinity, calcium, and salinity. Look for recent swings or out-of-range values.
- Assess water flow and light: Observe polyp extension and tissue movement. Adjust placement if polyps are retracted, torn, or excessively swaying.
- Look for aggression: Inspect for tissue recession or necrosis at contact points with other corals. Check for sweeper tentacles at night.
- Inspect for pests or fish: Watch for nipping fish or invertebrates. Remove or isolate offenders if found.
- Review recent changes: Consider if you’ve moved the coral, changed lighting, or altered flow recently.
Change only one variable at a time and observe the coral’s response for several days before making additional adjustments.
Aggression between coral species
Life as a coral must be tough. They are at the mercy of their environment and surroundings. But that doesn’t mean they are pushovers. Corals have adapted very sophisticated ways to protect themselves from competitors in their environments. Some corals and algae release chemicals, others attempt to grow over and shade out, and many, including the Frogspawn coral, try to sting their neighbors into submission. If you see damage at the border polyps between different species, you may have an issue with aggression.
The best bet, sometimes, is to trim back, or frag the corals, and/or relocate the colony or frags, to create more space.
Polyps being nipped by a not-so-reef-safe-saltwater fish
Occasionally, aquarium owners have one of those ‘usually reef safe’ fish species, that do nip at coral polyps enough to disturb the Frog spawn coral. If the nipping is aggressive enough, the coral frag may not extend its polyps, and trouble can result from that. The remedy here is to identify the problem and isolate the offending fish.
Polyps not opening-up
If Euphyllia divisa polyps aren’t expanded, it is certainly a sign that something is wrong. Check to make sure nothing is physically disturbing your coral (like a clownfish that wants the coral to be an anemone or a butterflyfish or angelfish with a polyp-nipping habit.
note retracted polyps
Please also check the water flow and water parameters. Remember the Goldilocks principle with respect to water flow and ensure the reef aquarium water parameters are stable. If the polyps are retracted, this may be a bellwether of less than ideal water conditions. Check those last entries in your reef journal and look for changing water parameters.
Sometimes, performing a simple water change can help get the water conditions back on track.
Physical damage due to handling
The large, fleshy polyps of LPS corals like the Frog spawn are prone to damage. You must be extremely careful when handling them, moving them, adjusting live rock nearby–and be careful to ensure that water flow is appropriate, or the polyps might tear.
Brown jelly infections
Brown jelly infections are a serious problem that can be encountered when keeping the Frogspawn coral. Typically, the first thing that happens is some sort of trauma or damage to the coral polyps themselves. The injured coral is then thought to be subjected to a protozoan infection–and those protozoans turn the polyps into a gross-smelling, disgusting-looking brown jelly (Borneman 2001).
Why Frogspawn corals are susceptible: Their large, fleshy polyps are easily damaged by handling, aggressive neighbors, or unstable water conditions, making them vulnerable to opportunistic infections.
Early warning signs: Localized tissue necrosis, brown or cloudy mucus on the coral, foul odor, and rapid tissue loss. Infected areas may appear as brown, slimy patches that spread quickly.
Prevention: Handle corals gently, avoid unnecessary movement, maintain stable water parameters, and quarantine new additions. Prevent physical damage from tools, tank mates, or strong flow.
Treatment: Brown jelly infections spread quickly across the whole coral, often killing the entire coral colony. The most effective response is rapid intervention: remove the colony from the water and cut away or frag any infected areas and some of the bordering healthy tissue. An iodine dip can help reduce pathogen load. Isolate the affected coral to prevent spread.
Bleaching
Corals that are severely stressed by some environmental queue, like perhaps being put too directly under the white-hot aquarium lights, may undergo bleaching–which is where the coral expels the photosynthetic symbiotic zooxanthellae. Depending on how serious the bleaching and stress are, the coral can sometimes be nursed back, or you may lose the entire Frog spawn coral colony.
Frogspawn coral care: how to frag
The branching variety of frogspawn coral, Euphyllia paradivisa, is fragged fairly easily by snapping, cutting, or sawing the branches near the base and using cyanoacrylate glue to affix the frag to your preferred piece of live rock.
Best practices for fragging Frogspawn coral:
- Use clean, sterilized tools to minimize infection risk.
- Cut at the base of the branch, away from the polyp heads, to avoid damaging tissue.
- Immediately dip new frags in an iodine solution to reduce pathogen load.
- Quarantine new frags for observation before returning them to the main tank.
- Avoid excessive handling or force, which can cause tissue tearing and increase susceptibility to brown jelly infections.
Common mistakes to avoid: Cutting too close to the polyp head, failing to disinfect tools, skipping the iodine dip, or placing frags directly into a high-flow or high-light area without acclimation.
What to read next
Check out a few of these other equally awesome and perhaps even more popular LPS coral types:
or find an entirely new coral type, Zoanthids or Mushrooms
References:
Borneman, Eric H. Aquarium Corals. Microcosm Ltd; 1st Printing Edition (March 1, 2001)
Ulrich III, Albert B. How to Frag Corals: Step-by-step guide to coral propagation and filling your frag tank with thriving polyps. www.SaltwaterAquariumBlog.com (January 20, 2015).
Ulrich III, Albert B. The New Saltwater Aquarium Guide. www.SaltwaterAquariumBlog.com (April 8, 2014)