Duncan Coral is a fast-growing LPS coral species ideal for beginner, intermediate, and advanced reef hobbyists. This coral species is known for its beautiful fleshy polyps, peaceful disposition, ease of care, and its ability to thrive in saltwater aquariums with low – medium lighting and medium flow comfortably.
Duncan Coral comes available in a variety of colors that you will find fancy, and the best part is beholding the coral’s whole body as it glows magnificently under full spectrum or actinic lighting. With the proper water conditions, lighting, flow, and feeding habits, this coral will grow and survive in your reef tank, and it will continuously put out new heads to increase its population.
Don’t know how to take good care of the Duncan Coral? Not to worry, this article provides valuable insights on the captive care of the Duncan Coral. It contains comprehensive information concerning its feeding, optimal water parameters, breeding, and lots more.
Quick Notes about Duncan Coral
|Whisker coral or Daisy coral
|Tank size (minimum)
|15 gallons (~60 liters)
|Low to medium
|24 – 27°C (~75°F – 80°F)
|SG = 1.023 – 1.025
|8.1 – 8.4
|8 – 12
|5 – 10 ppm
|Photosynthetic / require
|Bottom to Middle
|Moderate to fast
|Purple, pink, green, or blue-grey tentacles
Origin of Duncan Coral
As mentioned earlier, Duncan Coral is an LPS coral, and the origin of this species can be traced to the Indo Pacific — Australia precisely. Belonging to the genus Duncanopsammia, the Duncan coral Duncanopsammia axifuga is a monotypic taxon, in simpler terms — the only species of this genus.
Duncan coral is commonly known as whisker coral or daisy coral. It looks a bit like the button polyp, but the button polyps lack the fleshy tentacles and calcified skeleton found in Duncanops, yet their oral discs look the same. The taxonomical hierarchy of the Duncan coral is as follows:
Species: Duncanopsammia axifuga
Habitat of Duncan Coral
The Duncan Coral is indigenous to Australia. It dwells on sandy and rocky seabeds in Australia and the South China Sea.
These corals are predominantly found in waters over 20 meters (65 ft) deep, affixed to a solid substrate but in areas where soft sand is abundant. Therein, Duncan corals grow in colonies of clustered or branching individuals at the lower levels.
Description of Duncan Coral
This species has a calcified skeletal structure and a wide striped, teal oral disc. The coral possesses seemingly long fleshy tentacles which form around the edges of the disc. These are usually purple/pink, green, or blue-grey.
There is a disparity in the growth habit of the Duncan coral. It is capable of attaining compact/clustered growth form or branching out distinctively into individual fleshy heads attached on long, tubular collarites.
This LPS coral thrives on food produced by the symbiotic zooxanthellae living on its tissue, and it is also capable of feeding by actively capturing prey within its reach.
The Duncan coral will remain healthy and thrive for many years in a reef aquarium if proper water conditions are present.
Behavior of Duncan Coral
Duncan coral is prized for its peaceful nature, and it can coexist with other non-aggressive LPS corals and invertebrates.
The Duncan coral’s tentacles remain extended day and night and retract when disturbed. For example, when a curious fish nips at the polyps or aggressive tankmates move closer to its body. Other cases include the retraction of polyps due to excessive lighting or very high flow/water movement in the aquarium to circumvent severe damages.
Regardless, you should maintain adequate spacing between Duncan corals and other inhabitants like corals, sponges, and anemones in your tank if they possess lethal defensive mechanisms.
Duncans may not hurt them, but what about them harming your Duncans? Put this into consideration while housing the Duncan corals to avert possible problems.
Unlike many other corals (like Torch corals, Hammer corals, Frogspawn corals, etc.), that develop long sweeper tentacles to sting nearby corals, in the constant battle for real estate, the Duncan coral does not have ones.
This hardy coral is gentle and lacks sweeper tentacles, so it cannot inflict any injuries on tankmates. Try to give it plenty of room to grow since it will form many new polyps as time goes on.
The spacing will also help the coral avoid contact with tankmates, thereby assuring its safety and longevity in your reef tank.
Feeding Duncan Coral
The coral can receive nourishment through the photosynthetic activities of this symbiotic alga dwelling in its tissue.
Apart from this mode of nutrition, the Duncan coral will use its tentacles to capture plankton from the water column that it pushes further to the mouthpart located at the center of the oral disc.
Also, the Duncan coral will benefit from regular, supplemental feeding of small meaty foods and pellets. These include:
- reef roids (link to Amazon),
- finely chopped pieces of shellfish,
- vitamin-enriched brine shrimp,
- specialized pellet food, etc.
Important: Don’t just insert these food items into the tank and expect them to capture them. Instead, use a turkey baster or sea squirt feeder to squirt food directly on the polyps, your coral will respond by almost quickly expanding its tentacles to draw the meal in for digestion.
Tip: Frozen foods should be thawed and rinsed to make it easier for the Duncan corals to consume them. Also, rinse the chopped food several more times to remove as much phosphate from the food as possible.
Manual feeding should be 2 – 3 times a week, though the coral gets most of the required nutrients from photosynthesis. Supplemental feeding is equally important as it boosts the growth rate.
However, be sure not to overfeed your Duncans. They are voracious eaters. Their tentacles are very “sticky” and they have a really strong feeding response. For example, some people reported that their Duncan corals managed to catch and eat Asterina starfish.
Tank Requirements and Water Parameters
The Duncan coral grows fast and produces new heads with ease. While small tanks are not often ideal, larger tanks can contain a massive colony, and allow for proper spacing.
Water type, Temperature, Hardness, and pH:
Temperature: The ideal temperature for keeping Duncan coral is between 75 – 80 °F (24 – 27 °C)
pH: Recommended pH level is between the values 8.1 – 8.4.
Hardness: The coral will thrive best under moderate hardness with optimal values 8 – 12 dKH.
Specific gravity: Maintain specific gravity of 1.023 – 1.025 for the healthy growth of your corals.
Adequate medium lighting is vital to encourage the healthy growth of your corals. They can thrive in low – medium light conditions with ease, whereas high lighting may stress them out.
In the same vein, make sure to avoid placing the coral under direct metal halides as it will bleach and damage the coral’s tissue. Use full-spectrum LED lights or T5s’ to provide the required lighting levels; light outputs around 75 – 100 PAR is suitable for the coral’s lighting needs.
Another interesting feature of Duncan corals is that they generally will change colors depending on what kind of lighting you have. Whether it is white light or blue light, they will not stay the same color.
Duncan corals cannot handle very strong flow (like a palm tree in a hurricane), so be sure to provide moderate flow in the reef tank. The water flow should be enough to bring suspended prey or food closer to their tentacles and preventing detritus from resting on its body.
Also, avoid excessive or strong flow as it can harm the coral or cause its polyps to retract fully, thus hindering its ability to feed properly.
Note: When the flow is strong Duncan’s tentacles are usually short and blunt, less flow they are long and stringy.
Important: On the Internet, you will see a lot of conflicting information regarding lighting and flow. People say that they have had success with a strong flow and high light to low flow with medium light. First of all, it shows us that Duncan corals are hardy. Second, the general consensus that the reef community derived over years of experience is that moderate flow and medium light conditions are optimal.
Placement of Duncan Coral in the Tank
Duncan corals do not encrust to the plug.
Mount your Duncan corals at cool spots, preferably at the low – midsections of your aquarium, where it can obtain the medium lighting needed to conduct photosynthesis for its nourishment.
It is not recommended to place them on the sand, they get irritated easily if sand reaches them.
As for the positioning, straight up, midway up and horizontal – they seem to do the same either way. For example, a major colony of Duncan corals often grows into a ball where some face-up, some horizontal, and some even downwards.
Care and Maintenance of Duncan Coral
Duncan or whisker corals are hardy and relatively easy to keep. Endeavor to perform partial water changes, be it 20 – 25% monthly or 10 – 15% bi-weekly, this helps to keep the water clean and replenish the needed trace elements.
Make a habit of conducting routine water checks to ensure that the water parameters are in their appropriate ranges and proportions.
While at it, try to maintain the following additional water parameters always to promote optimal growth and health condition of your Duncan corals:
Calcium: 400 – 450 ppm
Magnesium: 1250 – 1,350 ppm
Salinity: 1.023 – 1.025
Strontium: 8 – 10 ppm
Phosphate: < 0.05 ppm
Ammonia: 0 ppm
Nitrates: 5 – 10 ppm
Do not lower your nitrates too low, it negatively affects these corals
Additionally, feed your Duncan corals at least 2 – 3 times every week to encourage speedy growth. Practicing target feeding will help ensure that the corals receive and ingest the meals within the shortest time possible, thus preventing them from being snatched by the tankmates.
Furthermore, monitor your Duncans and other tank inhabitants closely to be sure that they are healthy. Once you spot an unhealthy coral, relocate it to a separate or hospital tank for treatment till it heals.
Similarly, an exposed coral skeleton often hints at excessive lighting or water flow, hence cut back on these conditions. Besides, this could also be a sign of death if the coral remains that way after you have made necessary changes to the tank’s conditions. When this happens, don’t fret, do your best to salvage the remaining colony.
Some Problems Associated with Duncan Corals
- Brown Jelly: As the name suggests, this condition is characterized by a brown jelly-like goo. Brown jelly can be caused by poor water quality, tissue damage,
overfeeding, etc. When it occurs, there is a presence of brown jelly floating on the surface of the coral and this can spread like wildfire to the whole Duncan coral colony or other corals within the tank if not treated.
Solution: Frag the head off, brush, and siphon off any visible trace of brown jelly, use iodine dips, put it in a hospital tank, and prey for the best.
The unhealthy coral should be dipped in a freshwater dip (15 ppt) or iodine solution to eliminate the infection.
Broad-spectrum antibiotics are also potent enough to cure the brown jelly infection. Afterward, place the treated coral in a quarantine tank to recover fully before returning it to the main tank.
Do not overdose. Use the instructions on the bottle based on your tank size.
- Coral bleaching: In most cases, this is a response to environmental stress. It can be caused by exposure to direct lighting, changes in salinity, pH, etc. For example, according to the study, Duncan corals exhibited bleaching under elevated temperatures (32 C or 89 F) and high light intensity.
Temperature and light act synergistically to influence bleaching susceptibility. When this happens, the coral loses its color and turns pale or translucent since the symbiotic algae living in its tissue has been expelled. So, you have to find the cause and fix it.
- Do not open (retracting): Lot’s of aquarists complain that Duncan’s keep closing for several days and even weeks! Do not panic.
Normally it is either sprouting a new head or just sulking. Sometimes they take a few months to settle into a tank. They will open up normally but not seem to grow and … suddenly they grow like crazy.
Also, these corals have sensitive flesh. So, if something is consistently pecking at it (a Foxface, a Blue Tang, a Yellow Tang, a Flame Angel can do that), they won’t tolerate it for long before retracting to protect itself.
- Duncan coral abandoning base (Bailing out): It does not happen very often but in some cases, Duncan coral heads leave the old skeleton. While the real reasons for this are unknown, the reef community assumes that this is because of the swings in water parameters.
Too big of swings can stress the coral and stop calcification which will cause the polyps to detach. Test your water parameters regularly at the same time of day.
Fragging and Reproduction of Duncan Coral
These corals can reproduce asexually by budding off new individual polyps from the mature (parent) polyps to form new colonies.
The ability to produce new members at an incredibly rapid rate is one of the things everybody loves about the Duncan coral. One head can bud off as much as five within a couple of months.
Alternatively, one can frag a healthy coral to establish a new colony.
This should be done with precision using a band saw.
This process is simple, but you have to be cautious.
During fragging, keep your corals wet all the time, store them in a small bucket holding water taken directly from their home aquarium. You can also use this water for rinsing any flesh away from cuts.
- You will need a decent-sized Duncan coral with a few heads for this purpose.
- Take out the coral and irritate it a little bit, so that it will retract the tentacles.
- Using an electric bandsaw, divide the coral into several parts by cutting between polyps and always cut branches off as far below the polyp as possible.
Note: Do not use cutters or scalpel for this. The skeleton of Duncan corals is very dense. However, it is relatively easy to break if you hit it but I do not recommend doing it because the parts will be uneven.
- After cutting, treat the new frags in an iodine solution. This helps to disinfect cuts as they are made which has shown to greatly increase frag survival.
- Attach them to a frag plug using a cyanoacrylate gel and place them into the reef tank.
Tip: Take a frag plug and put it in the water for a couple of minutes to release the air bubbles that might be in the ceramic frag plug.
Tip #2: Treat the new frags with an iodine solution (for example, Lugol’s solution) to prevent them from contracting diseases, then you can attach them to a live rock before placing them back into the tank.
Buying Duncan Coral
When shopping for Duncan corals, make sure to look out for healthy specimens with good coloration, robust body, and fully extended polyps.
Duncans with drab or faded coloration, slime coating, retracted polyps might not survive in your reef tank, so it’s best to shy away from acquiring those.
Duncan corals are highly sought-after in the aquarium hobby, and many offline and online marine aquarium stores have this coral in stock. Endeavor to obtain specimens from reputable dealers who keep captive-bred stock and use safe propagation methods to ensure good health and survival.
Don’t forget to quarantine new corals. Dip them to remove potential pests. Examples (links top check the price on Amazon):
- Seachem Reef Dip,
- Blue Ocean Corals Coral Rx Dip Aquarium Treatment,
- Brightwell Aquatics Koral MD – Coral and Frag Dip Cleaner.
Duncan coral is a popular, hardy, and attractive large polyp stony coral species. A unique and excellent addition to established reef aquaria.
Duncans can be placed on the lower to midsections of the tank to adorn it with a delightful splash of vibrant green and purple.
This coral can thrive in reef tanks with low or medium lighting and flow. Also, certain reef aquarists have left this coral unattended for several weeks and reported no problems. Although that’s not a good practice, it shows how hardy and forgiving Duncan corals are.
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