Are you looking to create an epic SPS tank, but are wondering how you should care for Acropora corals? If so, you have come to the right place, as in today’s article I will cover everything you need to know about Acropora coral care, including some great Acros to get you started creating that mini-ocean you have always dreamt of!
What Are Acropora Corals?
Acropora corals very often referred to as Acros, are a genus of small polyp stony (SPS) corals, found in shallow waters, that grow into impressive branching colonies. Acropora colonies also include staghorns, elkhorns, and even flat encrusting tables.
Acroporas are the most iconic SPS coral when you visualize coral reef structures. They also represent most of the reef-building corals and are the largest and most contributing corals in the world.
Torch Coral Summary
- Scientific/Latin Name: Acropora (sp.)
- Family: Acroporidae
- Common Names: Acropora
- Care Level: Challenging
- Temperament: Aggressive (some are semi-aggressive)
- Lighting: High (PAR 200+)
- Water Flow: High
- Placement: Middle to the top region
- Growth: Moderate
Acropora Corals That Are A MUST!
Acropora corals have been widely propagated in captivity to help conserve wild populations. This is also beneficial for reef hobbyists, as corals that are grown in captivity are usually better acclimated to reef tank conditions.
Not only are the following Acros some of our favorites, but most of them are also great Acros for beginners!
Reef Tank Advisor’s Top Picks!
- Bali Green Slimer Acro
- Tri-color Valida Acro
- Walt Disney Acro
- Homewrecker Acro
- Strawberry Shortcake Acro
- Oregon Blue Tort Acro
- PC Rainbow Acro
- Aussie Dragon Scale Acro
- Acropora millepora
Origins And Habitat
Most Acropora corals come from the Indo-Pacific region, where coral biodiversity is at its best. With around 150 known Acropora species in the world, only three Acros are found in the Caribbean region. These three Acros are the staghorn coral (Acropora cervicornis), elkhorn coral (Acropora palmata), and the fused staghorn coral (Acropora prolifera). These three Acro corals are vital for providing refuge for juvenile fish and small invertebrates.
Acropora corals found in the Indo-Pacific region also play a critical role in coral reef ecosystems. In addition to providing refuge for marine life, Acros in this area are also responsible for making the calcium carbonate backbone in coral reefs. However, harsh conditions in shallow regions require some adaptations to survive. Because Acros grow in shallow areas where lighting is intense, they have adapted their hard skeleton to brace themselves from the constant wave action.
Unfortunately, there are only so many adaptations that SPS corals like your Acro can do in the wild. They are not able to adapt to destruction from trawlers, dynamite fishing, dropping anchors, and/or drastic changes from climate change, and as a result of this devastation, Acropora corals are becoming underwater graveyards, dying at worrying rates.
What Do Acropora Corals Look Like?
Acropora corals come in an impressive range of sizes, shapes, and colors. While most Acros form branches, many other forms such as tables, plates, columns, ridges, or clustering Acros are found, depending on the location in the ocean.
Acropora Reproduction & Growth Rates
Like most coral species, Acropora corals are both male and female, therefore they can reproduce both sexually and asexually. You can expect your Acro to reach sexual maturity within 3-5 years old.
In the wild, Acros release eggs and sperm at the same time, fertilizing an egg, and creating a free-swimming planula larva. The planula larvae will settle onto a substrate and will establish a small polyp that shortly develops into a coral.
Propagation in aquariums is easy for Acropora corals. When your Acro is healthy and is not showing any signs of stress, cut a 2” branch off and glue it to a spare frag plug or piece of rock. Give the frag ample water flow and glue it at an angle to promote faster growth.
Knowing how to grow Acropora fast is on every keen hobbyist’s mind. Unfortunately, there is no exact measurement of how fast your Acro will grow, as it depends on the species you have. However, experienced hobbyists have found that Acropora Corals that grow between 15 and 20 cm/year in captivity, are considered “good growers”.
You shouldn’t expect your Acro to fill your aquarium right away, as it can take some time for Acros to fully settle in, and you may even notice your Acro turning brown the first few weeks and months as they adapt to new conditions. Do not worry, this is normal and they will color up fairly quickly!
Acropora Coral Care & Maintenance
What makes Acropora corals challenging is their level of care, but ironically this is what attracts many hobbyists in keeping Acros in their aquarium. Taking on new challenges is the best way to improve coral husbandry and successfully keep difficult corals like Acroporas.
The challenge of keeping Acros comes from their high demands for lighting, water flow, pristine water chemistry, and stable water parameters.
Tank Parameters to Maintain for Healthy Acropora
- Temperature: 76° – 82 °F
- pH: 8.0 – 8.4
- Salinity: 1.024 – 1.026 (1.025 preferred)
- Alkalinity: 8 – 12 dKH
- Nitrates: <10 ppm
- Phosphates: <0.10 ppm
- Calcium: 350 – 450 ppm
- Magnesium: 1250 – 1350
In particular, you need to keep a close eye on alkalinity, calcium, and magnesium.
Alkalinity, calcium, and magnesium all help to build your Acros calcium carbonate skeleton and maintain its beautiful coloration. To prevent fluctuations, a dosing pump is highly recommended.
Acropora Lighting & PAR Requirements
Acroporas are one of the few corals that love light because they are found at the very top of coral reefs. They thrive with high-intensity lighting with a PAR of 300, however, some Acro species will be more successful with light intensities above 500 PAR.
Saying that, you should never expose new Acro specimens to intense lighting, as light overexposure can cause serious damage. Therefore, it is always recommended you slowly adapt your Acro to its new environment by placing your Acro at lower lighting locations and slowly moving it up towards its final destination.
Deciding which lighting fixture can be tricky, and over the last few decades, it is a hot topic that can sometimes become heated among hobbyists. There is no clear evidence which lighting fixture is best for Acropora corals, however, they tend to do better under metal halides or LED and metal halide hybrid lighting systems.
Whichever lighting set-up you choose, for best coloration, it is recommended you provide your Acropora Coral with an 18-20K color spectrum.
How many hours of light does an Acropora need?
Just like their relatives, Acroporas have the same photoperiod requirements as SPS and LPS (large stony polyp) corals. Your Acro will thank you with bright coloration if you give them around 7 to 9 hours of lighting per day. Of course, your lighting settings may be different from others, but anything far out of this range can cause issues for your Acro.
If you provide too much lighting, you may experience your Acropora turning white. This is from coral bleaching, where a coral becomes stressed, expelling their symbiotic algae (zooxanthellae) in response, causing them to turn white. If you do experience your Acro turning white, do not worry, as most often bleached Acropora corals can recover.
Water Flow Requirements
Water flow is critical to provide your Acropora with the nutrients required for growth and that mesmerizing coloration, plus it is also important to have strong enough water movement to remove any waste and to prevent algae and other marine debris from settling on your coral’s polyps.
As already mentioned, Acropora corals are used to living in the top area in coral reef ecosystems, therefore they are more comfortable with a high water flow. Because Acros are also used to a lot of water movement from wave action, not only does your Acro require high water flow, but it will also need a random water flow pattern.
While it is true that your Acropora coral can get most of its nutritional requirements directly from the symbiotic algae that live within their tissues, called zooxanthellae, many Acropora corals can also catch prey in the water.
Your Acro gets its nutritional requirements from amino acids, small zooplankton (rotifers and cyclops plankton), and nitrogenous waste produced by fish. Coral foods such as Reef Roids and New Life Spectrum Reef Micro Food are readily available online or at your local fish store (LFS).
As Acros have small polyps, you should aim for food between 0.5 and 2 mm in size, and for precision and ease, target feeding is highly recommended.
By feeding your Acropora coral, your coral will thank you with faster growth and brighter coloration.
Acropora Placement In The Aquarium
Your Acropora coral will need to be placed where there is plenty of light and water flow. Every aquarium setup is different, however, these conditions are usually at the top and middle parts of an aquarium.
When deciding where to place your Acro, you also need to consider its temperament. Acropora corals like their personal space, so allow plenty of room to avoid chemical warfare, plus, this allows them to grow into impressive structures that they are well-known for – let’s just say, they are quite the show-off in SPS-dominated reef tanks!
Acropora Temperament & Aggression
When corals start to grow in a confined area such as a reef tank, life can start to become crowded. Many corals are known to be aggressive, and sometimes different corals will attack their neighbors by stinging them to survive or to outcompete for space. Some, however, don’t mind having a neighbor or even touching each other, which is typically true if you place two of the same species of coral together.
While Acros may not look aggressive, once two aggressive Acros start, it can be difficult to control after the “coral battle” is in full swing! Some Acros will battle it out to a stalemate, while other Acros don’t give up, and will continue to fight until the other coral has taken significant damage, or has been killed.
If you are worried about your Acropora corals getting too close, monitor their temperament and move them to a more suitable area, just in case one experiences some serious damage.
Suitable Tank Mates For Acropora Corals
Acropora corals do best when they are receiving natural nutrients (poop) from fish. The good news for you is that Acropora corals can be kept with all reef-safe species of fish.
But, some fish like butterflyfish are largely considered to be not reef-safe, however, many hobbyists have found that they are more likely to pick on any LPS or soft corals first before trying to nip on SPS corals like your Acropora. However, always be mindful if you do add any fish that are regarded as not reef-safe.
Acropora Pests, Diseases & Common Problems
Sometimes you may have to face your worst nightmares when keeping corals, and those are common problems, pests, and diseases.
Rapid & Slow Tissue Necrosis
Acropora corals are prone to rapid/slow tissue necrosis (R/STN), a disease that is common with SPS corals both in captivity and in the wild. Tissue necrosis degrades the coral’s tissues, often killing the entire colony, and turning the Acro white.
The difference between STN and RTN is that STN takes days to months to strip the tissue, whereas RTN can occur in hours. There is still not enough evidence why it affects corals, however, lack of water flow, high temperatures, and elevated phosphate and nutrient levels are thought to be linked.
If your Acropora coral starts showing signs of RTN or STN, you can try dipping it in an iodine solution or propagating in the hope that some frags can regrow. If you do not frag the colony, the tissue necrosis will likely spread like wildfire.
Acropora Eating Flatworms
Acropora Eating Flatworms are difficult to see because they can mimic the coloration of your Acropora coral. When infected by AEFW, your coral will likely turn brown and then show white bite marks from the worms. If an infestation has occurred, you can treat your coral with pest control dips. If you need to treat the whole aquarium you must run activated carbon to remove the treatment which will protect other organisms in your tank.
Red bugs are less of an issue, but they are difficult to treat as they are very small and can be resistant to coral dips. Aquarium hobbyists have been successful in using more aggressive dip treatments such as Interceptor (Milbemycin oxime) which is used to treat worm disease and internal parasites in dogs. When dipping, you should always consider the damage from treatment and never expose your coral for more than 25 minutes.
Where To Buy Acropora Corals
Acropora corals can be found in your LFS or from online reef shops. When you are searching for an Acro, it can be very difficult as there are so many to choose from!
One thing that I cannot stress enough is the reputation of the seller. This is critical as you do not want to order a coral that looks epic, but when it arrives it is not what it looked like in the picture online. Online stores that put “WYSIWYG”, simply mean “what you see is what you get” and these are what you should look for when buying Acropora corals online.
Once you have bought your Acro, and it arrives, it is a very exciting time, but don’t forget to properly acclimate your new Acropora coral. Acclimating your Acro coral will gradually allow it to adjust to its new home.
How To Frag Acropora
If your Acropora coral has started to grow, it may be a good time to grab those cutters and do some fragging! Fragging your Acropora is not only profitable, but it is often necessary when colonies start to outgrow your reef tank.
Luckily fragging is not difficult, and if you have ever fragged another branching SPS coral before, you will be a pro, because the method is the same.
If you want a clean-cut edge, then an electric saw is recommended, however, if you do not have one or feel uncomfortable using an electric saw, a bone cutter will still do the job!
Simply cut off a piece of your Acro and dip it in a coral dip like CoralRX or an iodine bath to recover. Remember, if you are selling on your Acropora frag, ensure you cut off a nice healthy piece that is very colorful.
Acropora corals are the “crown jewels” of the aquarium world, and with so many sizes, shapes, and colors, you can see why they are one of the most iconic SPS corals in the aquarium trade.
While the rumors are true, Acropora corals are slightly challenging due to their demanding needs (high lighting, high and random water flow, and pristine water conditions), taking on a challenge is part of becoming a better aquarium hobbyist, plus there are also some great beginner Acro corals you can start with.
Whichever Acropora coral you decide to bring home, they will, no doubt, blow you away, creating that picturesque home reef aquarium you have always dreamt of.