Your One-Stop Guide To Acan Coral 

May 6, 2022

acan coral

Picture credit: Haplochromis (CC License)

Acan coral is a favorite amongst reef keepers for all the right reasons. It’s compatible with a myriad of coral species, is undemanding, and looks absolutely stunning.

But it is known to throw a curveball every once in a while that even catches veteran hobbyists off guard. 

You’ve come to the right place if you just got a new Acan coral or are looking to get one. This is the care guide you were looking for. Hehe! 

This guide will include pretty much everything you need to know about raising acan corals successfully at home. You’ll be somewhat of an expert by the end of this article. 

So, hop on! 

Acan Coral In A Nutshell 

Acan coral is sometimes known as Acan Lords. What a fitting name, right? Well, it’s actually a shortened form of their original species name – Acanthastrea lordhowensis. Still a fitting name. 

First things first – the name is actually kinda misleading.

Although they were initially classified in the genus Acanthastrea in 1848, they were reclassified to the Micromussa genus in 2016. DNA research showed that they were closely related to the Micromussa genus. 

So, their real name now is Micromussa lordhowensis.

Nonetheless, they’re still known and loved as acan coral, and we will be using this name throughout the article. 

Here’s what their scientific classification looks like:

  • Kingdom: Animalia 
  • Phylum: Cnidaria 
  • Class: Anthozoa 
  • Order: Scleractinia 
  • Family: Lobophylliidae 
  • Genus: Micromuss (previously Acanthastrea)

The wow factor of these corals is the diversity of colors they can display. For instance, a single specimen can show off blue, purple, green, and red tones under the same lighting!

Acan corals are often hailed as the easiest LPS corals to raise and grow. Besides the dazzling colors, they’re best known for their fast growth rate, hardiness, and ability to adapt to just about any reef environment. 

Their natural distribution is quite widespread! They mainly occupy shallow reefs in the Indo-Pacific region, around countries like Australia and Japan. 

Temperament-wise, these corals are pretty aggressive. They’re known to sting and don’t make amicable neighbors. Instead, they will use their sweeping tentacles to attack potential prey or predator right next to them. 

That being said, their aggression can be kept under check for the most part by allocating plenty of space for each individual specimen and its tentacles. 

Acan corals are deemed suitable for most beginners as long as one’s willing to put in some effort for regular maintenance. They are quite hardy and forgiving of beginners’ mistakes to begin with. 

Acan corals can cost anywhere between $10-15 per head on the fragment. The price they fetch largely depends on the color and size of the coral. 

Acan Coral At A Glance 

  • Name: Acan Coral
  • Other Names: Micro Lords, Acan Lords
  • Scientific Name: Micromussa lordhowensis 
  • Colors : Purple, Red, Green, Blue, Gray, Brown, Orange, Pink 
  • Minimum Tank Size: 10 gallons (40 liters)
  • Care Level: Easy to moderate
  • Propagation: Easy to moderate 
  • Growth Rate: Fast
  • Tank Placement :Bottom
  • Feeding: Photosynthesis 
  • Water Flow: Low to moderate
  • Temperature: 23 – 26°C (74°F – 80°F)
  • pH: 8.1-8.4
  • Carbonate Hardness: 8-12
  • Specific Gravity : 1.023-1.025
  • Nitrate: Less than 10 PPM
  • Toxicity: No
  • Temperament: Semi-aggressive 

Acan Coral’s Natural Distribution 

Acan corals are found in reef environments of the Indo-Pacific region at depths of 0-30 meters (0-98 feet). 

Their natural distribution ranges from the Red Sea, Eastern African Coast, and Gulf of Aqaba to the East China Sea, Australia, and the Solomon Islands. 

The most commonly kept Acan species is Micromussa Lordhowensis, monikered after Lord Howe Island. However, they’re also rampantly found across Australia in the Elizabeth Reef, Flinders Reef, Middleton Reef, Burrup Peninsula, and Dampier Archipelago. 

Acan Coral Appearance 

Marine hobbyists often sought coral for the beauty and pop-up of color they lend to their environment. And I don’t think any other coral meets this description very well than an acan coral. 

Acan coral has corallites (skeleton formation under each polyp) that have even walls height-wise. Thus, the coral has a uniform and almost symmetrical appearance. 

The collarite is a skeletal cup formed by an individual stony coral polyp, in which the polyps rest and retract into. It can be around 15mm (0.6 inches) in diameter. 

The septa, positioned near the wall of the collarite, are thick and have tall fine teeth. 

Observing the polyps of the acan coral when not fully expanded shows that the walls are being shared – therefore contributing to the identification. 

Thanks to the polyp’s plump and fleshy appearance, tiny folds appear like an accordion when they retract. 

In the wild, acan coral colonies are usually large and flat – reaching about 2-3 meters in diameter. They are colonial corals that form clumps that can reach over 2 yards across. 

Lastly, acan corals are available in varying color combinations and patterns, including green, orange, red, blue, and purple. 

For example, the lordhowensis species comes in contrasting shades of green, blue, pink, purple, orange, or red. 

If you are looking for a particular color, it might take longer to find a suitable stock. And it will, of course, be a bit costlier too. 

There are different kinds of acan corals that vary quite a bit in appearance, although their care requirements are identical. 

Let’s have a look at 3 most commonly found acan coral types:

Acanthastrea echinata is the most widely found acan variation. It usually has red, orange, or green shades but can be found in some other colors as well. In terms of size, these corals are somewhere between A. bowerbanki and M. lordhowensis. These corals have a smooth appearance and are relatively flatter. 

Acanthastrea bowerbanki is the biggest kind of acan coral available out there. They have a bumpy texture and are flattened. They usually grow in irregular shapes. 

Corals from Micromussa lordhowensis are often known as micros due to their petite size compared to the other two coral species. These corals come in an array of different colors and patterns. 

Acan Coral Behavior And Temperament 

Acan coral isn’t really the most mannered coral available out there, but they’re not downright aggressive either. They’re best described as semi-aggressive corals. 

Coral aggression is a concept that seems to have come straight out of sci-fi movies. For starters, they look like plants and are immobile or semi-mobile. 

But, oh boy, are they equipped with a wide variety of chemical and physical defenses they employ in constant warfare for living space and food. 

These corals are known to get along quite well with others from the same species but are hostile towards others of different colors and species. They have sweeper tentacles that extend conveniently at night and sting nearby corals. 

Thus, they should be kept at a proper distance. 

And that’s not all. 

They can invert their stomach onto a nearby coral and digest its tissue right out of the skeleton if close enough. And once the ‘enemy’ is digested, they will swiftly retract their tummies back inside. 

Lastly, acan corals grow by producing new heads, eventually leading to a dorm shape when fully grown. They are known to grow so rapidly that they sprout a new head once every 7-14 days, given that diet and environmental parameters are maintained. 

Cutting to the chase, acan corals are semi-aggressive. They can launch their digestive tract at a nearby meal and digest it without any hiccup. Therefore, you should provide plenty of space to avoid confrontation between different parties. 

Acan Coral Tankmates 

Even though semi-aggressive, acan corals can be paired with several other coral varieties and fish and inverts as long as there is enough space to spread tentacles without touching anyone. 

Any coral beyond 4 inches should be safe from the acan’s sweeper tentacles and mesenterial filaments.

If you’re concerned about your corals engaging in chemical warfare, add activated carbon to counter it. But, of course, you will also need to perform regular water changes. 

Some compatible coral species include:

  • Plate coral
  • Favia coral
  • Chalice coral 
  • Mushroom coral
  • Blasto coral 

Some compatible reef-safe fish and inverts include:

  • Dwarf angels
  • Basslet
  • Firefish
  • Cardinals 
  • Clownfish 
  • Damselfish 
  • Snails 
  • Sea urchins 
  • Starfish 
  • Gobies
  • Tang
  • Blennies
  • Certain wrasses 

The recommendation about gobies and blennies should be taken with a pinch of salt. While both of them are reef-safe species, they may choose to use the acan coral as perches, which can cause the coral to retract. 

And while this won’t injure the coral, it may very well inhibit photosynthesis and nutrient intake. 

Also, it’s pretty unlikely for a coral to grow and reproduce if it is constantly being picked on or stressed by a fish or invert hanging around it.

Some tankmates to avoid include:

  • Anemone-eating invertebrates 
  • Fish that eat coral polyps
  • Butterflyfish 
  • Damselfish
  • Pufferfish
  • Triggerfish
  • Parrotfish 
  • Camel shrimp
  • Atlantic peppermint shrimp
  • Peppermint shrimp
  • Sensitive stony corals 
  • Most crabs

Most crabs and damselfish are some of the biggest offenders of acan corals. Also, do proper research before adding fellow inverts like shrimp. Some are good matches, while others will wreak havoc. 

Is Acan Coral Hard To Keep?

Caring for acan coral is not hard. In fact, they’re considered one of the easiest LPS corals to raise for. They’re pretty forgiving of a beginner’s mistakes. 

Acan corals are super hardy and will adapt without any qualms in just about any tank. Thanks to their low lighting requirements, they make great additions to hard-to-fill shaded areas in the tank. 

While acan corals are hardy, it shouldn’t be an excuse to keep them in subpar environments, right? General tank maintenance is quite crucial. Keep the tank clean by performing partial water changes and wiping away algae. 

If exposed to subpar conditions for long, acan corals will pick up disease just like anyone else in the tank. Treating the disease can be pretty tricky. Therefore, make an effort to keep the parameters right in the first place. 

You may also have to frag the coral to save healthy parts and get rid of the infected parts. 

Despite being easy to look after, these corals aren’t actually favored by hobbyists because they don’t bring exciting movement to the reef tank like some other LPS corals do. Another reason is that they don’t grow very fast. 

Minimum Recommended Tank Size For Acan Coral 

The minimum recommended tank size for acan coral is 10 gallons. But that’s only going to be enough if you plan to keep just a single acan coral. 

Given their tendency to sting others and conduct chemical warfare, I’d recommend housing them in at least a 29-gallon tank if you plan to keep other inhabitants too. 

It’s crucial to ensure enough space for corals to avoid touching one another. 

And if you are raising a coral community, you might want to opt for an even bigger tank since acan corals love being placed in low-light regions and are quite unfriendly towards their neighbors. 

You can allow more peaceful, high-light corals to dominate the central regions of the tank while acan coral beautifies the bottom and the corners. 

Acan Coral Placement 

The best spot for acan coral is the one with moderate water flow and light intensity. Also, the coral should be placed at least 6 inches or farther away from neighboring corals. Exposure to too much water and light will destroy the coral. 

Likewise, lack of social distancing means the acan coral might attack other corals in the vicinity. 

Remember, acan coral is a large polyp stony coral, so the water flow shouldn’t be as high as required for small polyp stony (SPS corals). Otherwise, you’ll end up ripping their delicate flesh. 

As I said above, the lighting should also be moderate – somewhere in the middle. If you think about their natural habitat in the wild, it’s quite deep and away from intense sunlight. 

Therefore, if you opt for an intense lighting scheme to ‘spotlight’ their colors, it’ll cause your corals unsolicited stress. 

Actinic lighting works fine and helps those vibrant shades pop. A PAR between 25-50 can split the desired difference between their photosynthesis needs and your desire for a well-lit reef tank. 

Water Parameters For Acan Coral 

  • Temperature: 23 – 26°C (74°F – 80°F)
  • pH: 8.1-8.4
  • Salinity: 1.023-1.025
  • Ammonia: 0 PPM
  • Nitrite: 0 PPM
  • Nitrate: Less than 10 PPM
  • Alkalinity: 8-12 dKH
  • Calcium Level: 350-450 PPM
  • Magnesium Level: 1250-1350 PPM
  • Phosphorus: 0 PPM
  • Flow Rate: Low to moderate

The list above shows that acan corals thrive the best in standard water conditions. However, it’s pretty essential to keep the parameters stable at all times. As with most coral species, acan coral should not be the first coral added to a new setup.

Acan corals thrive the best in fully established tanks that have been running for at least 6 months or more. A mature tank will have finished the cycling process and wouldn’t be prone to sudden changes in parameters. 

And since acan corals are LPS, they require a good concentration of calcium, magnesium, and other elements in the tank to ensure the proper growth of their stony skeletons. 

As these corals prefer being fed from time to time, maintaining a protein skimmer is quite essential to keep the tank’s nitrogen and organic waste levels low. 

Lighting For Acan Coral 

Unlike most stony corals, acan corals thrive the best in environments that don’t receive much light. As a matter of fact, overexposure to light will acutely stress them out. 

The light’s intensity should be just around 25-50 PAR for acan corals, and that directly translates to placing them as low as possible in the tank. They can also be placed around or under the corals but still maintain some social distance to avoid warfare. 

And by the way, an essential aspect of acan coral care is their highly variable coloration. The light’s intensity and type (incandescent, fluorescent, etc.) will cause coral to express different colors. 

Play up with the colors until you find a light regime that is the right mix of color and intensity and provides aesthetics and functionality at the same time. 

Usually, actinic lighting (color temperature 10,000K+) works well to bring out the deeper color tones of acan corals.

But note that actinic lighting is not very practical for photosynthesis. Actually, 9 out of 10 times, it’s used just for its aesthetic qualities. You’ll have to combine actinic lighting with white/yellow lighting (color temperature 6700K) to ensure the proper growth of corals. 

Here’s an Amazon link to light that we use and recommend using. 

Besides being energy-efficient and promoting photosynthesis, this actinic light emulates the softer shades of blue light, mimicking dawn, dusk, and deep waters. 

Feeding Acan Coral 

Like the rest of the corals from the LPS family, acan corals have developed several feeding strategies. Besides intaking nutrients via a symbiotic relationship with zooxanthellae, also known as marine algae, they also capture food particles and planktonic organisms from the water column and absorb dissolved organic matter. 

Since these corals are not finicky about their food, it’s pretty easy to feed them. They are very willing and quick to eat. You simply have to place the food in the center of the polyp. 

Plus, you have to consider all 3 of their feeding techniques while planning their diet regime. 

They mostly consume microscopic phytoplankton in the wild, also called marine snow. Marine snow refers to floating detritus and dissolved organic compounds. 

Some hobbyists prefer feeding their acans every day. But closed systems like tanks are naturally inclined to have more detritus and dissolved organic than original reef environments. 

Therefore, if you were to follow my opinion, I wouldn’t recommend feeding every day. 2 to 3 times every week will do. 

Here’s a list of food they can safely eat:

  • Copepods 
  • Shrimps 
  • Artemia
  • Chopped seafood
  • Frozen mysis 
  • Marine pellets 
  • LPS coral pellets 

Corals don’t look or behave like a typical animals. Therefore, it’s quite easy to start treating them like plants – even more, once you get to know about their photosynthesis process. 

However, they will struggle to grow and experience stunted growth if their dietary requirement is not fulfilled. 

When first introduced to a new environment, corals may deter eating. This is expected behavior. They’ll only become comfortable eating once they have fully acclimated and settled in the tank. 

While acan corals aren’t fussy about what they put in their mouths, broadcast feeding with larger food particles isn’t really recommended because uneaten food will contribute to poor water quality down the road. 

Instead, it is advised to practice target feeding to ensure the coral is well fed. For example, you can use a turkey baster or pipette to precisely direct the meal to their heads. And don’t forget to turn off the pumps for easier target feeding.

While acan corals are nocturnal feeders for the most part, they can be trained to eat whenever convenient for you. 

Breeding Acan Coral 

Acan coral are hermaphrodites. They possess both male and female gametes within 1 body. In nature, they can reproduce both sexually and asexually. To reproduce sexually, they rely on tides and lunar cycles that usher mass spawning. 

Since they are broadcast spawners, in oceans, they mate by releasing eggs and sperm simultaneously, resulting in fertilized eggs. The eggs then go on to become free-swimming planula larvae. And after a couple of days, the larvae will settle onto the substrate and become planksters. 

As you can guess, it’s implausible this will happen in the tank. 

Nonetheless, acan corals are excellent coral species to frag as they have large corallites, which are actually the skeletal cups that corals build under their actual flesh. 

When you frag an acan coral, it’s pretty easy to get whole corallites without inflicting harm on any of their neighbors. It’s also notable that they have a pretty fast recovery period from being fragged as long as they are adequately fed. 

Here’s a step-by-step guide on how to frag acan corals. 

Step 1

Ensure your hands are sanitized, or wear a pair of gloves. 

Step 2 

Single out individual polyps and cut down the center of the polyp. You can do so through the mouth, and they can be cut into quarters or halves. You can cut using a blade, sharp scalpel, diamond band saw, bone cutter, or dremel. This is the most tricky step. Be careful – you don’t want to break the coral’s skeleton. 

Step 3

Cut around all of the eyes of the acan coral. 

Step 4 

Treat the new frag pieces using an iodine solution to prevent them from contracting any infection. You can then attach them to a live rock before putting them back in the tank. 

Step 5

Glue the piece to a frag plug. The corals will quickly regenerate and will probably be ready to feed within hours to days. 

We use a fragging kit by DDP that comes with just about every piece of equipment you need to get going. 

Acan corals grow real fast. So it’s not uncommon to see new heads popping up just a few days after cutting a new frag. However, if there’s not enough space, the growth rate will slow down. So instead, they’ll grow by excreting more skeletons and mounding into a larger shape. 

Problems Associated With Acan Corals 

As hardy as acan corals are, they are not indomitable. The 3 most commonly associated problems with acan corals are bleaching, yellow blotch disease, and white pox. 

Let’s have a brief look at them before we end this article. 

Coral Bleaching

As the moniker suggests, coral bleaching is characterized by the coral’s flesh turning translucent and pale, exposing the skeleton. The most common reason behind bleaching is the expulsion of zooxanthellae that share a symbiotic relationship with the corals. 

Now, this, in turn, happens when there’s excessive lighting, consistent exposure to higher water temperature, sudden changes in salinity, and so on. 

Yellow Blotch Disease 

Yellow blotch disease manifests as small circular spots of translucent tissue with a yellowish tone across the base of the coral. The thing with this condition is that only the affected part of the coral will look somewhat off – the rest of the body retains natural color. 

This disease is caused by a bacteria that causes yellow lesions and attacks zooxanthellae algae within the coral – compromising the coral’s ability to perform photosynthesis efficiently. 

White Pox

The white pox disease is caused by gram-negative bacteria known as Serratia marcescens. The disease expresses itself as white spots across the coral’s body. The spots will multiply in size and number as the contamination spreads and consumes the coral’s tissue. 

Buying Acan Corals 

Acan corals can be easily purchased at pet stores and through online channels. The price will vary depending on the coral’s size, color, and rarity. There are a lot of leeways here, but you can get one or two heads of polyp frag for $20. But some rare variations can cost $100 and up. 

Final Words: Acan Corals 

Acan corals look pretty. And they’re pretty easy and a joy to raise as long as you get a couple of things right. Moreover, they’re undemanding – and thus, suitable for most beginners. 

These large polyp stony corals boast a unique structure and variety in patterns and colors and will effortlessly be the centerpiece of any reef tank. 

Recommended Readings!

Your One-Stop Guide To Elegance Coral

Your One-Stop Care Guide To Torch Corals 

Your One-Stop Guide To Kenya Tree Coral 

rohit gurung author at urbanfishkeeping

About Rohit Gurung

My never-ending love and fascination with Aquascaping started when I received a red-eared turtle for my 10th birthday.

Apart from researching and writing, I spend hours gazing at my 3 turtles. And yeah, I bask alongside them too.