Cyphastrea Coral Care

Cyphastrea are a massive reef building species and are part of the stony coral family Merulinidae. In the hobby they are available predominantly in an encrusting variety although there are unusual branching AND plating varieties available from time to time. They are much less common but it just goes to shows the diversity of this coral.

Cyphastrea are one of the hottest corals in reef keeping right now. Just a few years ago they were relatively unknown and not widely available for purchase but that changed in recent years as more and more people successfully propagated the various color morphs. For years the prevalent color morph was the red and blue meteor shower variant, but now there are so many that you could make an entire reef out of just different types of Cyphastrea and have your bases covered for color and growth patterns.

It isn’t difficult to see just why Cyphastrea captures the heart of so many reef keepers. They are an attractive coral with uniquely spaced polyps, and the fact that they are being aquacultured has all kinds of benefits for both overall sustainability and robustness of the individual corals.

As for color, Cyphastrea are able to color shift to some degree. They are not as variable as Acropora that can totally shift palate but Cyphastrea can definitely become more vibrant and colorful when they are happy and they can take on a more drab appearance when grown in suboptimal conditions. Any number of factors can affect their appearance such as changes in light, water chemistry, nutrition, or stressful events like shipping. They might lose some color during transit, but over a relatively short period of time they will color back up quickly if given the right conditions.


Despite the fact that these corals are easily aquacultured, there is still an influx of Cyphastrea from wild colonies collected from both Australia and Indonesia which has its benefits as well as more and more color morphs are discovered and made available in the trade.

Now that we covered some background on Cyphastrea, let’s look at some of their care requirements.

 Lighting and Placement

Cyphastrea are one of the easiest stony corals to care for and it is often recommended to reefers who are delving into hard coral care for the first time mainly because it loves lower light conditions.

If there is one coral you do not want to put in strong light or even moderate light to begin with it is a Cyphastrea because it takes a long time for them to adjust to high intensity light. We recommend lighting intensity under 100 PAR to start and if you want to move them into higher light conditions, do so very slowly. There are not a lot of benefits to giving this coral an over-abundance of light and it introduces substantial risk of overexposure. When in doubt, go with dimmer light and if you want to try and acclimate them to a brighter area of the tank do so slowly, and be prepared to move it back to shadier areas at the first signs of trouble for example if it starts to bleach or the polyps remain tightly closed.

Low Light

Low light translates to about 30-50 PAR

Medium Light

Medium Light is between 50-150 PAR

High Light

High Light is anything over 150 PAR

Lighting is a loaded topic, so for a more in-depth discussion of lighting, please see our Deep Dive article.

 Water Flow

One important factor worth mentioning about Cyphastrea is the amount of flow you provide. They require a moderate, indirect flow to ensure that no detritus builds up on their body. As they grow however their shape can become more of a detritus trap and you may have to change things up to keep them clean. If the detritus is allowed to build up it will over time kill the coral underneath. So it is worth bearing this in mind for both placement and for the shape you plan the coral to grow out in as some shapes will be much easier than others. Cyphastrea are mostly encrusting however we have seen very uncommon plating and branching varieties.

One last bit about water flow. If you want to feed them directly, you will want to be able to completely shut off the flow because any flow will wash away the food before the coral has a chance to grab and eat it.

Speaking of feeding regimens, let's move onto Cyphastrea feeding requirements.


I will be the first to say that most hobbyists do not target feed Cyphastrea and it may be more effort than it is worth. If you turn off the flow and provide them with appropriately sized food, they do take in a fair amount and slough off the rest. If you do decide to target feed them, there are a couple sources of food that work well, amino acids and small zooplankton.

Starting with amino acids, they are simple organic compounds containing a carboxyl (COOH) group and an amino group (NH2). Organisms use them for building proteins and are also necessary for other biological functions such as neurotransmitter transport and biosynthesis. The amino acids needed vary on a species by species basis but practically speaking, even if certain amino acids go un-utilized by a certain coral they will be taken up quickly by another organism for their biological process. There are several commercially available amino acid additives and you can also DIY your own solution from a mix of amino acid powders.

Small zooplankton include things such as rotifers and cyclops plankton. The rotifers we feed are usually around 0.5mm in size. Cyclops plankton are larger typically between 1-2mm. They come frozen and are basically a small granular oily paste that creates an orange cloud when introduced into the tank. The presence of rotifers in the water is immediately apparent to the corals because many of them will immediately open up and start their feeding behavior. You can see here one polyp is trying to eat a mysis shrimp. It’s a bit too large for them, but I have to give that little polyp credit for his ambitious appetite.

I have to mention that although coral nutrition is important, it is equally important to make sure to not overfeed the aquarium. Overfeeding can lead to issues that can be a hassle to overcome. A little bit of feeding goes a long way but all of the benefits can be wiped out by a nutrient overload caused by overfeeding especially considering Cyphastrea are not the most aggressive feeders in the world.

 Water Chemistry

Let’s move on to the topic of water chemistry for Cyphastrea. They are a fast growing stony coral and as such, they require some extra attention in comparison to soft corals or slow growing large polyp stony corals. There are three major chemical parameters that are needed by Cyphastrea to build its stony skeleton. These are Calcium, Alkalinity, and Magnesium. The chemical interaction of these three is a little out of the scope of this video but we can do a quick summary of all three starting with Calcium.

Calcium in most reefs hovers around 425 parts per million (ppm). In solution it is a bioavailable ion that is taken in by a number of different organisms such as calcarious algae, inverts, and coral (obviously) to build calcium carbonate structures. It doesn’t swing as wildly as some other water parameters, but it is a good idea to test it every now and again to make sure it stays in the general vicinity of natural sea water. This is especially true in aquariums with fast growing stony corals like Cyphastrea that will soak up more as they grow larger.

Alkalinity is a little more difficult to explain than calcium. It is not a particular ion, but a collection of ions, and can be thought of as the buffering capacity of saltwater. Buffering capacity is the amount of acid required to lower the pH of saltwater to the point bicarbonate turns into carbonic acid. In layman’s terms, higher alkalinity levels equate to greater chemical stability in our reef tanks. In practice alkalinity tends to be the parameter that fluctuates the most of the three and is the one that needs the most babysitting. In the wild, the alkalinity of the water is around 7 dkh, but I like to have our a little bit higher at around 8-9 dkh. There is some anecdotal evidence that slightly higher alkalinity levels promotes coral growth and it also provides some additional buffering capacity.

Maintaining steady levels of Calcium and Alkalinity can be a little tricky because of how they interact. For example, if your reef tank had a calcium level of 300ppm when you desire a value closer to 400ppm, you could theoretically add a calcium supplement to boost it. Unfortunately, reef aquarium chemistry is dynamic and solutions to chemistry issues are rarely that straightforward in practice. Addition of a calcium supplement in this manner often comes with a corresponding fall in alkalinity.

This see saw effect between calcium and alkalinity stems from how the two ions interact with one another. The two ions combine to form calcium carbonate and fall out of solution, thus lowering both levels. If you are experiencing this in your systems, the possible culprit with calcium and alkalinity instability is Magnesium. It may seem counterintuitive, but the three ions interact regularly.

Magnesium behaves similarly to calcium. It can bind up carbonate ions thus increasing the overall bioavailability of alkalinity compounds in the water. So again if you find that no amount of tweaking calcium and alkalinity directly is helping, you may want to make sure it is not your magnesium level that is in fact low. Magnesium levels are around 1350 ppm.

Remember, just maintaining levels is tricky. Fast growing SPS tanks experience rapid growth, and larger colonies soak up calcium, alkalinity, magnesium and trace elements at a much faster rate.

In smaller, lightly stocked aquariums regular weekly water changes are often enough to keep these parameters stable, but in most cases additional supplementation is required especially as Cyphastrea grow larger. The three most popular methods of maintaining these parameters are a kalkwasser topoff, Calcium Reactor, some type of 2-part dosing whether manual or automatic, or some combination of all of them. You can keep a successful reef using any of the above methods it is just whatever suits your budget and your time availability in order to get the most stable parameters possible. Which one or combination of methods that is best for you depends a lot on the requirements of your system and how much work you do on your tank.

 Pollution Parameters

Calcium, Alkalinity, and Magnesium aside, you also need to pay attention to your nutrient levels. By nutrients we are referring to Nitrates and Phosphates. Cyphastrea is adaptable and will survive in lower nutrient as well as higher nutrient situations BUT these levels will impact their appearance. Too much nutrient and the coral might turn an unattractive brown color. Too little nutrient and they might take on a pale emaciated appearance.

Given the choice between the two, I would prefer a slightly higher nutrient level. Nitrate and Phosphate are not bad in and of themselves. Elevated levels can cause problems, but they are absolutely required for biological processes in coral and cannot be produced through photosynthesis. Cyphastrea will not tolerate zero nutrients especially without significant amounts of supplemental planktonic coral foods or amino acids.

I generally try and shoot for Nitrate levels around 5-10 ppm but wouldn’t freak out if they were slightly higher around 25 ppm. Similarly, I try to keep my Phosphates around 0.01 to 0.05 ppm. If those figures get too high, it may slow down their growth or cause them to take on poor coloration. Worst case scenario, those chemical parameters lead to other problems like algae blooms which is both unsightly and can compromise the health of the corals in your tank.

 Propagation and Aquaculture

When it comes to sustainability, Cyphastrea are a bright spot for Propagation and Aquaculture. Cyphastrea make an excellent choice for both commercial aquaculture and to home propagation due to their exception growth rates. All the different color morphs available in the hobby today are a result of successful propagation because Cyphastrea are relatively infrequently imported so most of the frag sized pieces you see available are likely farmed.

They grow so well in captivity that it is important to stay on top of the frags by trimming otherwise you will find it overgrowing the frag rack.


So who is Cyphastrea for? This is a great beginner friendly coral that can find a home in a variety of tanks ranging from mixed reefs to shadier sections of an SPS dominated tank. They have a very unique appearance and come in a wide array of color variants so if you are a collector, Cyphastrea will definitely keep you busy tracking down all the different colors.

Thank you for reading. Until next time, Happy Reefing.

Than Thein

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