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Fellow reefers, we have all been there. We are so excited to buy a new coral and the excitement is quickly followed by fear that we won’t know how to care for it properly. Fortunately a Duncan Coral is one of the easier LPS corals to keep in the hobby. However, they are a coral and require proper care. And being an LPS corals there are other parameters that come into play when it comes to growing a healthy colony of Duncans.
We’re going to go over the basics of how to care for your Duncan Coral. When you are done reading this post, you should have all that you need in order to keep your coral happy and healthy in its new home. Let’s get started!
A Quick Overview Of The Duncan Coral
|Scientific Name||Duncanopsammia axifuga|
|Common Names||Duncans (abbreviated from their genus name), rarely referred to as the whisker coral or daisy coral|
|Common Colors||Purples, blues, greens|
|Lighting||Low-High (<50-200 PAR)|
|Tank Placement||Bottom, Middle, Top|
|Temperature Range||76-82 degrees F|
|pH Range||8.0 – 8.4|
|Salinity||1.025 or 35 PPT|
|Alkalinity||8 – 12 dKH|
|Calcium Level||350 – 450 PPM|
|Magnesium Level||1250 – 1350 PPM|
Origins And Habitat
The Duncan coral is the only species within the Duncanopsammia genus and originates from the waters surrounding Australia. More specifically, these corals can be found off the western and northern coasts of Australia and as far away as the South China Sea.
There, these corals thrive in many conditions but prefer sandy areas. Once established in large colonies, it can be difficult to see any of their branching skeleton. Duncan corals are a recent addition to the aquarium hobby and have only been available for about 15 years.
What Do Duncan Corals Look Like?
Though duncan corals might look fleshy from above, they are actually a type of large polyp stony coral (LPS). This means that each polyp is supported and sheltered by a hard calcium carbonate skeleton.
Duncan corals are an easy coral species to identify if you know what you’re looking for. Usually seen in tight colonies, these corals have wide polyp heads surrounded by tentacles with a mouth in the center. Some Duncans may have longer tentacles than others, but they’re relatively short. The center of the polyp usually stays under a few inches wide across.
These polyps are typically a mixture of purples, blues, and greens, though these colors might change and intensify under certain lighting. Almost all Duncans have a blueish-green center with light pink or purple tentacles. These tentacles are harmless to fish and other corals, though Duncans should be given their own space within the aquarium.
It is believed that this Duncan skeleton is much stronger than other LPS. The Duncan coral is a branching species, which means that each polyp head will extend from its own individual section of skeleton.
Though there is only one known species of this coral, the degree of branching can vary greatly between specimens. Some Duncans have tight and compact branching whereas others have very long tree-like branches where each polyp is very far from the next.
In general, the Duncan coral appearance is likened to elegance corals (Catalaphyllia jardinei) and Euphyllia spp., like hammers and frogspawns. However, Duncans are considered to be even easier to keep than those and are accepted as one of the best beginner corals in the hobby.
Are They Easy To Keep?
Duncan corals are considered to be one of the easiest LPS corals to care for and are great for beginners. As we’ll discuss, these corals can adapt to a variety of water conditions and tank setups.
That being said, Duncan corals are not the most popular coral to have in your tank. This is because they can be slow growing, uninteresting to look at when compared to other corals, and take up a lot of space in the aquarium.
If you don’t want to spend a fortune on coral if you’re just starting out, then Duncan corals are a good choice! Give them some time in your tank and you might even grow a larger colony that can be traded for more desirable species.
Placement And Temperament In The Aquarium
Duncan corals are extremely adaptable and can live in most conditions if acclimated properly. Hobbyists have kept Duncans at the bottoms of their reef aquariums in the shadows, or right next to Acropora small polyp stony coral (SPS) at the highest PAR values.
Though these corals can be placed anywhere from low to high reef lighting, their color doesn’t change with intensity. Instead, Duncan color is highly influenced by the spectrum of the light being used; they might show more neon variations under actinic lighting than a light focused in the other spectrums.
Duncan corals do need good flow and should be placed in a medium to high current. This is because they are very susceptible to being taken over by algae due to stagnant areas in the colony; they are also voracious eaters and will want to catch any available food in the water column.
If flow allows, these corals can be placed on the substrate or on the rockwork. Placement doesn’t need to be cautious of other corals as Duncans are completely harmless and cannot sting. That being said, they can easily be attacked by more aggressive corals which will cause them to close and eventually die.
Duncan corals can also quickly shade out other species below, so make sure you allow your Duncan enough room to grow to full size.
Care And Maintenance
Duncan corals are very low maintenance and are able to sustain themselves with good lighting, flow, and available nutrients. They can tolerate relatively large swings in water parameters but do best in optimal water conditions.
Like most other corals, Duncans need stable water parameters. Most importantly, they need some nitrate to be available in the aquarium in order to grow and maintain their color.
Too clean of an aquarium will not allow your Duncan corals to thrive, and will usually be reflected in other coral development as well. Because these corals are LPS, they need ample levels of calcium and stable alkalinity in order to form their skeletons.
If keeping larger colonies of Duncan or if placed in a mixed reef aquarium with SPS, then it may be necessary to dose those depleted nutrients. Otherwise, regular feedings and water changes will be enough to keep nutrients available.
Duncan corals do not require any special filtration and can be kept with a hang on the back filter, canister filter, or sump filtration. A protein skimmer is not necessary, especially if the system does not have many nutrients available.
One of the best features of Duncan corals is their willingness to eat almost anything you give them. Unlike many other LPS, Duncans are actually very willing to use the mouth at the top of their polyp head to ingest both small and large pieces of food.
Duncan corals can be fed an assortment of foods, including mysis shrimp, krill, pieces of seafood, as well as coral-specific powder formulas and pellets. These corals are voracious feeders and will accept these foods when offered. However, in order to keep nutrients down, it’s only recommended to target feed about one to two times per week.
Duncan corals will readily accept food that is placed near their mouths, though this can take some time to move the food and digest it. In that time, fish and invertebrates may steal the food and annoy the coral in the process.
The best way to stop this from happening is to broadcast feed at the same time to stop them from stealing the food. A great coral food to use to feed Duncans would be Reef Roids.
What Are Good Tankmates?
Duncan corals are not able to defend themselves like most other corals. The only thing they can do is retract if something starts to walk over them or attack them.
This is especially important to keep in mind when choosing other corals to place around your Duncan. Aggressive corals with long sweeper tentacles, like favia corals (Favia spp.) and torch corals (Euphyllia glabrescens), should be avoided or placed far away from your Duncan colony.
Otherwise, duncan corals can be kept with a variety of reef-safe fish and invertebrates. Some options include:
- Damsel Fish
- Select wrasses
Gobies and blennies are also on this list but have been known to excessively swim and walk over Duncan corals that might be placed on the substrate. Invertebrates, like species of cleaner shrimp, should also be avoided for this same reason as they can cause your corals to be closed more than you would like.
Other invertebrates with pincers and an appetite for fleshy corals should never be placed in a reef tank either. This includes emerald crabs (Mithraculus sculptus) and banded coral shrimp (Stenopus hispidus).
For as easy as Duncans can be for some hobbyists, they can sometimes be as temperamental as zoas! For the most part, though, solving Duncan coral problems is straightforward and usually a matter of adjusting lighting, flow, or pests.
Why Is They Not Opening Up?
The most common problem to have with Duncan corals is the failure for them to open or extend completely. Don’t panic though! Duncan corals are very easy to save if things go wrong and it’s just a matter of looking at what could be causing the problem.
Lighting and flow
If you have a relatively new Duncan coral or just recently rearranged your saltwater tank, your Duncan might not be happy with its new placement.
Duncan corals can tolerate most light intensities, even when next to SPS, but this does not mean that they can go from very low light to bright light without any acclimation. If you find that your Duncan coral is not extending, try moving it away from the light. Slowly work back up towards that level in the tank instead.
The same solution goes for water flow. Duncans do best in moderate to high flow. Not enough flow can cause algae to grow and irritate the coral while overly high flow can start to cause tissue damage. You want to find a happy medium between these two extremes; a good placement would bring soft movement to all tentacles of the colony. Work with adjustable wavemakers or gyre (like the IceCap Gyre) to make things easier to adjust in your aquarium.
Believe it or not, a closed Duncan can actually be a good sign!
Sometimes these corals will close up for a few days while they develop new heads. These heads will be near the base of the polyp and lighter in color. If you notice these and hadn’t seen them before, then your coral is happy and growing!
If you don’t see any new heads, check out other reasons as to why your coral might be closed.
Though Duncans can quickly adapt to new conditions, they still need to be acclimated like all other corals, invertebrates, and fish.
Most hobbyists don’t feel the need to drip acclimate their corals, but a temperature match is definitely recommended. A coral dip or quarantine period is also strongly recommended before adding the piece to your tank to avoid disease and pest introduction.
Before placing your coral in its final spot in the tank, it is best to leave it on the substrate or on a frag rack for a couple of weeks so that it can adjust to your tank’s parameters. Then, slowly move the frag to the desired placement.
Lastly, pests can be the cause of your angry Duncan coral. If something like Aiptasia or hydroids start growing on the skeleton of your Duncan, it can easily irritate the polyp, causing it to start retracted.
Pests can be hard to see and you might need to take a magnifying glass to the side of the tank, but your coral should make a full recovery once the pest has been removed.
Most Duncan coral problems are straightforward, though it’s always scary to have to handle your corals.
If you can’t find any reason as to why your Duncan corals might be closed, try enticing them to open. This can be done with target feeding to encourage your coral to eat. Try not to do this too much, though, as you can irritate the coral and build up nutrients within the tank.
How To Frag
Duncans are one of the easiest and most forgiving species of coral to propagate. As a branching species of large polyp stony coral, simply use a bone cutter or electric saw to cut the skeleton below the flesh.
Fragging is the best way to control Duncan growth or to spread the coral around the tank. Fragging can also be helpful if one section of the colony is damaged or has been infected by pests.
Here is how to easily frag your Duncan colony:
- First, remove the coral from the tank. Try to keep the coral submerged in water as much as possible.
- Carefully cut the coral with the bone cutter or electric saw between where the flesh starts and the branching begins.
- Attach this frag to a frag plug with superglue (cyanoacrylate).
- Dip your coral. Dipping your Duncan in a coral solution or iodine is highly recommended to promote fast healing, but this is not entirely necessary.
- Put the frag back into the tank, preferably on a frag rack or in the substrate; make sure that the coral is secure and won’t fall over.
- Gradually more the coral up to its final spot in the tank or rehome it to another hobbyist.
If you are looking for a more visual example, our Aussie friends at Gallery Aquatic TV give a great example below on how to frag these Aussie originals.
While Duncan corals might not be the most popular LPS coral to have in the reef aquarium, these beginner corals bring movement to the display. They can be placed in almost all lighting intensities with acclimation, which can fill up empty spots in the aquarium. Duncan corals do require moderate to high water flow and will close for extended periods of time if conditions are unideal. However, they are very easy to frag and one of the most forgiving species to propagate.
We want all Duncan owners out there to know how much we appreciate them for taking the time to read this article. Leave us a comment below if you’ve got any questions about caring for your own Duncans!
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I’m thrilled that you found Aquarium Store Depot! Here you’ll find information on fish, aquariums, and all things aquatics related. I’m a hobbyist (being doing this since I was 11) and here to help other hobbyists thrive with their aquariums!