Duncan corals are one of the easier Large Polyp Stony corals to keep, making them extremely popular with reef hobbyists.
This guide explains how to care for this beautiful LPS coral, including its preferred tank conditions and water parameters. When you’ve finished reading, you should have everything you need to keep your coral happy and healthy, so let’s dive in!
Duncan Coral – At a Glance
|Duncan Coral Info|
|Scientific Name||Duncanopsammia axifuga|
|Common Name||Duncan coral, Whisker coral, Daisy coral|
|Colors||Purple, blue, green|
|Lighting||Low-High (<50-200 PAR)|
|Tank Placement||All areas|
|Flow Rate||Moderate to high|
|Temperature Range||76 to 82o F|
|pH Range||8.0 to 8.4|
|Salinity||1.025 or 35 PPT|
|Hardness||8 to 12 dKH|
Origins and Natural Habitat
Duncan coral is the only species within its genus and comes from the waters around Australia, specifically off the northern and western coasts and as far as the South China Sea.
Here, the coral thrives in many conditions, although it prefers sandy areas, where it establishes large colonies. Duncan corals are a pretty recent addition to the marine hobby and have only been available for around 15 years.
Duncan Coral Appearance
Although Duncan corals appear fleshy when viewed from above, they are, in fact, a type of LPS coral, meaning that each polyp is sheltered and supported by a hard skeleton of calcium carbonate.
These corals are quite easy to identify, growing in tight colonies, they have wide polyp heads with a central mouth surrounded by relatively short tentacles. The polyp center is typically less than a few inches wide.
Duncan corals come in a mixture of green, purple, and blue shades, although those colors sometimes become more intense or change under certain lighting. most Duncans have a bluish-green center surrounded by pale pink or purple tentacles. Although the coral’s tentacles are harmless to other tank residents, we recommend giving them plenty of space within your aquarium.
Unlike many other types of LPS, the Duncan’s skeleton is thought to be much more robust. This coral is a branching species, meaning that each polyp head extends from its own section of the skeleton. Interestingly, even though there is only one known species of Duncan coral, branching varies tremendously between specimens. Some are tight and compact, whereas others have long branches where each polyp is located far away from the next.
Are Duncan Corals Beginner-Friendly?
The Duncan coral is regarded as one of the easiest LPS corals to look after, making them a good choice for beginners.
That said, this coral is quite slow-growing, takes up a fair bit of space in your tank, and isn’t particularly interesting to look at. However, if you want an inexpensive coral and you’re just starting out in the Marine hobby, the Duncan is a great choice!
Duncan corals can cope with most conditions, provided you acclimate them properly.
You can place this coral anywhere in your aquarium under low or high lighting conditions without changing the intensity of its color. However, Duncan coral color is very much influenced by the light spectrum being used, with the coral showing more neon variation when kept under actinic lighting than a light that’s focused in the other spectrums.
To ensure their healthy growth, it’s important to ensure that Duncan corals receive adequate flow. You should place them in an area with moderate to high current, as stagnant sections in the colony can lead to an overgrowth of algae. As these corals are avid feeders, they tend to catch any available food drifting by in the water column.
If the water flow is adequate, you can place these corals either on the substrate or on your rockwork without worrying too much about other corals since Duncans are harmless and cannot sting. However, Duncan corals are susceptible to attacks from aggressive species, which can cause them to close up and eventually die. In addition, Duncan corals can grow quickly and shade out other species placed beneath them, so you must give them enough space to reach their full size.
Duncan Coral Care Guide
As previously mentioned, Duncan corals are quite easy to take care of and can thrive on their own when provided with sufficient lighting, water flow, and nutrients. They are resilient to significant changes in water quality but prefer to live in optimal conditions.
Duncan corals, like most other coral species, need stable water conditions to thrive. The water temperature should be between 76 and 82o F, with a pH level of 8.0 to 8.4 and a water hardness of between 8 to 12 dKH.
To maintain the Duncan’s color and growth, some nitrate must be available in the aquarium, so keeping the tank too clean can hinder their development, as well as that of other corals.
Like all LPS coral species, Duncans need enough calcium and alkalinity to form their skeletons, and for larger colonies of these corals or those kept in a mixed reef aquarium with SPS, dosing depleted nutrients is usually necessary.
Duncan corals don’t require any special filtration and can be kept with a sump filtration, a hang-on-the-back (HOB) filter, or a canister filter. You don’t need a protein skimmer unless your system has an excess of nutrients.
What To Feed Your Duncan Corals
Duncan corals have a mouth at the top of their polyp head that can eat both small and large pieces of food. These voracious corals have a varied diet, including shrimp, mysis, pieces of seafood, krill, and coral-specific powder formulas and pellets.
However, it is recommended to target feed Duncan corals only once or twice a week to keep nutrients at an optimal level. Although the corals will happily accept food placed near their mouths, it can take some time for them to move and digest the food. During this time, fish and invertebrates could steal the food, irritating and stressing the coral, and to avoid that, it’s best to broadcast feed at the same time.
Duncan corals are less equipped to defend themselves than other coral species and can only retract when threatened or disturbed. Therefore, it’s crucial to remember that when choosing other corals to be placed around your Duncan colony. Avoid aggressive corals like Favia spp. and Euphyllia glabrescens with long sweeper tentacles, or place them far away from the Duncan colony.
You can keep Duncan corals with a variety of reef-safe fish and invertebrates, including the following:
- Damsel Fish
It’s important to note that placing Duncan corals on the substrate can cause stress on them, especially when Gobies and blennies swim and walk over them. To keep your corals healthy, it’s best to avoid invertebrates like cleaner shrimp which can cause them to close. Additionally, it’s not recommended to add invertebrates such as Mithraculus sculptus and Stenopus hispidus to your reef tank as they have a tendency to have pincers and feed on fleshy corals.
The most common problem hobbyists experience with Duncan corals is that they don’t open or extend completely. However, the issue is generally pretty straightforward to solve; it’s just a case of working out what could be causing it.
Lighting and Flow Rate
If your Duncan coral is relatively new or if you recently changed its placement in your tank, it might not be happy with the new spot.
Although Duncans can tolerate most light intensities, sudden changes from very low light to bright light can stress them out. Therefore, we recommend you acclimate your coral slowly by moving it away from the light and gradually increasing the light level in your aquarium.
The same applies when it comes to water flow. Duncan corals thrive in moderate to high flow, but insufficient flow can cause algae growth that irritates the coral, while overly high flow can damage the organism’s tissue. To find the perfect flow rate, you should aim for a happy medium that provides soft movement across all the colony’s tentacles.
A closed Duncan coral can actually be a very good thing! Sometimes, the corals close for a few days while they develop new heads. The new heads are close to the polyp base and are lighter in color than the rest of the coral, and if you notice these, you know your coral is happy and growing well.
Although Duncan corals are known for their adaptability, it is still essential to acclimate them like any other coral, invertebrate, or fish.
Although most hobbyists skip the drip acclimation process, we highly recommend matching the water temperature. It’s also a good idea to quarantine or dip the coral before introducing it to your tank to prevent the spread of disease and pests.
To be sure your coral adjusts well to your tank’s parameters, we recommend placing it on a substrate or a frag rack for a few weeks before moving the organism to its final position. Once the coral has fully acclimated to the new environment, gradually move the frag to its desired location.
It’s worth noting that certain pests can stress your Duncan coral. For example, if you notice Aiptasia or hydroids growing on the coral’s skeleton, it’s possible that the polyp will become irritated and start to retract.
Although pests can be difficult to spot, and you might need to use a magnifying glass to spot them, once you remove the invaders, your Duncan coral should make a full recovery.
How to Frag Duncan Corals
If you love Duncan corals and want to grow more, you’ll be pleased to learn that fragging them is pretty easy.
To control the growth or spread of the coral in the tank, you can frag it. Fragging involves cutting the skeleton below the flesh using a bone cutter or electric saw. This technique also comes in handy if any part of the colony is damaged or infected by pests.
Here’s how to go about fragging your Duncan colony:
- Remove the coral from the tank and keep it submerged in water as much as possible.
- Use a bone cutter or electric saw to carefully cut the coral between the branching and where the flesh starts.
- Attach the frag to a frag plug using superglue (cyanoacrylate).
- Although it’s not mandatory, it can be a good idea to dip the Duncan frag in a coral solution or iodine to promote fast healing.
- Put the frag back into the tank, making sure it’s secure and won’t fall over, ideally on a frag rack or in the substrate.
- Gradually move the coral up to its final spot in the tank or give it to another hobbyist.
Although Duncan corals might not be the most well-known LPS coral for a reef aquarium, they add a nice touch of movement to your display and are a great choice for beginners to reef tanks.
With proper acclimation, these corals can thrive in various lighting intensities and fill in any empty spots in your tank. Adequate water flow is essential for these corals, and they can close up for extended periods if water conditions aren’t ideal. However, the Duncan coral is very easy to propagate through fragmentation and is one of the most tolerant species out there.