When it comes to corals, beginner saltwater aquarium hobbyists might shy away from hard corals. A lot of information online discusses the difficulty of caring for hard corals and suggest that only soft corals are suitable for those of us who have just started our journey into coral care.
Of course, stony corals do need more care than soft corals, but Acropora corals are one of the best genera of hard corals to look after in a saltwater aquarium, and we are here to provide you with a simple and easy care guide for Acropora corals, suitable for both novices and beginners!
These corals are sensitive to changes in the water flow, temperature, and chemistry, and this is why many beginners might be put off having them in their tanks. However, fully understanding the needs of these coral means that you are able to create and maintain the best environment for them to survive.
What Are Acropora Corals?
Firstly, let’s look at what Acropora corals are and why you might want them in your saltwater aquarium.
Acropora refers to the genus of coral and is a stony coral with small polyps. They have a high metabolism and light skeletons which means they are quick to grow! In the wild, Acropora corals make up a huge amount of coral reefs.
There are many different species of Acropora corals and are mostly all found in reefs in the Indo-Pacific areas, such as Fiji, Tonga, and the Great Barrier Reef.
Longhorn, Table, and Elkhorn are all popular types of Acropora corals that are available to saltwater aquarium enthusiasts.
What Do Acropora Corals Look Like?
Most species of Acropora corals are brown or green, but you can get them in brighter colors, or with wonderfully different shades and contrast. We have some beautiful red ones and purple ones. This makes them a wonderful addition to a saltwater aquarium and a truly captivating sight. Their colors are known to change in captivity, so watch out for this!
Acropora corals grow as plates or branches. Some branches are thick and stubby, and others thin. There is a huge variety within Acropora corals when it comes to shapes and how they grow depends on where they are in the ocean rather than what species they are. For example, Acropora corals found in deep water with little water flow tend to be long and thin but you might also find one of the same species with thicker branches.
How To Care For Acropora Corals
These corals tend to be a little tougher than other stony corals, but they still are a bit fussy when it comes to their environment! Because of this, the situation in your saltwater aquarium needs to be right for them before you are wanting to add them in. You must also be aware of how to care for the corals once you have them!
In order for Acropora corals to thrive, you must need the lighting and heating in the aquarium to be perfect.
Because of the zooxanthellae that live in the coral’s tissue, you must have adequate lighting in your aquarium. Acropora corals tend to flourish under a decent amount of light and need a minimum of 3 watts per gallon. Strong lighting from a VHO or metal halide will provide the corals with the lighting they need.
These corals do well in tanks that are 100 gallons or larger. You need to add them into a stable aquarium that is at least a year old. When you have put the coral in your tank it is advised to not move them after that because it can really stress them out.
Acropora corals need a heavy water flow as this is where they thrive in nature. A turbulent water flow means that the nutrients the corals need are brought to them, and their waste is taken away. These corals enjoy a random, mixing current with water coming from different directions.
If the corals are not provided with the correct water flow they become extremely susceptible to diseases that might cause bleaching or even death.
When first putting the coral in your tank, do not set the water flow as too turbulent until the coral gets time to settle. Then, as it gains density, increase the water flow.
The sensitivity of Acropora corals means that you need to keep an eye on the chemicals in the water. These stony corals need nutrients to grow, and therefore they will die if these things are not in the water.
You must have the correct amount of calcium in your tank, between 400 – 450ppm. You also need to keep an eye on the levels of alkaline and magnesium in the aquarium and attempt to keep them as close to natural ocean water as possible. However, if you are making any changes to the chemistry of the water remember to do this slowly as any big changes can harm the marine life in your saltwater aquarium.
When it comes to hard corals, you must be really attentive to the levels of nitrates and phosphates in your tank. Bad quality water with high levels of nitrates and phosphates will really affect the health of your Acropora corals and cause them to deteriorate.
Keep the amount of phosphates in the tank as close to zero as possible and keep the level of nitrates under 5ppm.
To keep your Acroporas healthy, it is important to feed them. Of course, they get a lot of their nutrients from zooxanthellae, but to make sure they are getting everything they need you should feed them once a week.
Dosing Acropora corals with phytoplankton is a great way to give your corals what they need. Anything bigger might be too difficult for them to eat.
Acropora corals do well when living with a range of reef safe fish. This creates a wonderful natural habitat for them. However, crabs are known to damage Acropora coral.
They are fairly calm corals and live well with other SPS corals. However, they are known to sting other corals that are around them. It is advisable to keep colonies at safe distances from each other. Remember to provide them with enough space to grow.
Acropora corals are susceptible to a number of diseases and illnesses, so it is good to know what to look out for and what to do if any of these things occur.
One illness that Acropora corals are known to suffer from is rapid tissue necrosis (RTD). This is where the tissue on the coral begins to peel off. It can be a bit frustrating for hobbyists as RTD can be caused by a lot of things, such as changes in temperature, lighting, and saliency, and therefore you might not know what to do to fix it!
In order to try and save the Acropora coral, you might want to cut it into frags, focusing on the healthy parts. Putting the healthy fragments into a fresh substrate means that some of your Acropora might still survive!
Your Acropora coral might also suffer from bleaching, which is where they expel the small zooxanthellae that are living within their tissues. In order for you to avoid this, make sure that there aren’t any sudden changes in your saltwater aquarium. If bleaching has occurred there still is a chance that they will get better, so make sure you are keeping the temperate, water flow, and chemicals in the tank at a constant.
Acropora corals might also face issues with certain pests, mainly red bugs or flatworms. Red bugs are fleas on the coral that will irritate them and they need to be removed, even though they are not a massive threat to the health of the coral.
Flatworms are more of an issue when it comes to corals as they can cause death. Thankfully, they are pretty easy to get rid of. Check out our in-depth article about how to get rid of flatworms here.
The Wonders of Coral
Acropora corals are a wonderful species of stony coral and look great in any saltwater aquarium. Hopefully, this guide has given you all the knowledge you need to look after a healthy Acropora coral! They can be hard to look after, but with the right technique, you will be able to maintain a strong and happy Acropora coral.
Enjoy the wonders of coral and have fun watching them thrive under your care!