Acropora Coral Care Guide

What are Acropora

Acropora are a type of branching SPS Coral (Small Polyp Stony) often found in shallow waters. Acros are a brightly colored coral that creates branching structures where fish and invertebrates can live. They make up large portions of the coral reef and are simply stunning to look at. Acros are very sensitive to changes in water chemistry, temperature, light, and easily stressed. So this makes them ideal for experienced reefers that can focus on stability.

There are multiple types of Acropora coral, including some that create shelf-like structures, known as "shelfing acros", and some that create more of a branch-like structure. Many of these acropora corals require very similar care though.

Acropora Care - Temperature

Temperature Stability

The first thing with any coral is temperature. Many reefers believe that if they are within a given range, they will be fine. However, when keeping sensitive corals like SPS, especially acropora, stability is key. Keeping the temperature within a 0.5 degrees F or so is very important to reducing coral stress.

Ideal Temperature

When researching Acropora Care, I found an article from Reef Builders that answers this question based on their coral farming experience. In their article, Reef Builders notes that they found Acropora to show the best coloration at a temperature between 73 and 74 degrees F. However, Reef Builders also notes that for the best Acropora growth, they keep temperatures between 77 and 79 degrees F.

If you are reading this, the odds are that you're a home reef keeper. Meaning you likely have other coral to think about, and will want to keep the coral at about 76-78 to keep them all happy. So I would choose a temperature in that range.

Acropora Coral Care - Alkalinity, Calcium, and Magnesium

Alkalinity

Like most SPS coral, Acropora thrive with stability, more so than an exact number. That being said, I have found that many of the most successful acropora coral reef keepers, such as those over at Frag Box, keep their alkalinity in the 7 to 8 dKh range.

You will want to measure alkalinity at least twice per week, but as much as once per day. I highly recommend using a Hanna Checker for this.

Calcium

When it comes to acropora care, stability is key. Calcium levels are not as important as alkalinity, but you should try to maintain within about 10 or 20 ppm of your target calcium levels. The ideal calcium target is between 400-450 ppm. You should test calcium once every week or two. When testing Calcium, the Red Sea Calcium/Ca Pro Test Kit is one of the best when it comes to finding a sweet spot between accuracy and speed.

Magnesium

In general, acropora care should focus on other parameters before magnesium. Maintaining a standard level around 1300ppm is ideal. If the level sways slightly, begin to make minor adjustments. Anywhere between 1200-1400ppm is acceptable. Measuring once every 2 to 4 weeks with a Red Sea Magnesium Pro Test Kit is sufficient.

Acropora Coral Care - Nitrates and Phosphates

Though you don't want to be absolutely zero on Nitrates or Phosphates, you also don't want to be too high either. The ideal levels for Nitrates is between 1 and 10 ppm. Phosphates should be roughly 0.01 - 0.05ppm.

The reason for having some nitrate and phosphates in your tank is due to research showing that coral need nutrients to enhance their growth and coloration. Too much of either, however, will slow growth and reduce coloration.

Acropora Coral Care - Flow

Flow for acropora coral care is another important factor. It brings the good chemicals to the acropora and removes the bad nutrients and waste from them.

In addition to the "obvious" flow for coral and acropora care, it's important to know that acros grow differently based on how much flow they have. When provided large amounts of flow, acros will tend to grow thicker branches, and with less flow they will branch more. Studies seem to show that this is likely in order to maximize the amount of beneficial bacteria between the branches, which the acropora will then consume to grow more.

For more about Reef Aquarium Flow, visit my post on Reef Aquarium Flow.

Acropora Coral Care - Lighting

Acropora tend to thrive best under strong lighting. The most success for acropora care comes in between 200 and 400 par. When introducing new acropora, start with lower lighting locations, and work the coral upward to the desired point. Some acropora prefer 150 - 200 PAR and some prefer higher PAR in the 300 - 500 range. It really depends on the species.

For more about the different types of lighting, see the Reef Stable Saltwater Aquarium Lighting Guide.

Acropora Coral Care - Placement and Aggression

Though there are not any stinging tentacles, acropora will sting nearby corals and other SPS. It is best to keep distance between acropora and any other coral as they may attack each other. Though most often placed at the top of the tank, the placement should be based on lighting, flow, and proximity to other coral.

Acropora Coral Care - Feeding

According to an article on Reef Builders, the best way to feed Arcopora is to provide a plankton bloom for a few hours, and then provide a large water change. Tidal Gardens recommends feeding acropora using amino acids and small zooplankton, such as rotifers and cyclops plankton.

Though being photosynthetic, acropora do not require feeding at all.

Thoughts on Acropora Care from Tidal Gardens

Pests and Common Problems

Coral "Peeling" - STN and RTN

Slow Tissue Necrosis and Rapid Tissue Necrosis are when the skin on the SPS coral, such as an acropora, begin to peel off and die. When it comes to acropora care, it is important to stop any stressors that may cause STN and RTN before they occur. Frag Box has noticed that when caring for acropora, they see STN and RTN more commonly in tanks where the alkalinity is above 10dKh. This further empasizes keeping the home aquarium between 7 and 8 dKh.

If your alkalinity is at the high end of the spectrum, you can reduce the alkalinity by not dosing 2-part and allowing your coral to consume the alkalinity until it is at the desired level. You will want to measure alkalinity at least once, if not twice per day during this process. I highly recommend using a Hanna Checker for this.

Acropora Eating Flatworms (AEFW)

Acropora Eating Flatworms are small clear blob like worms that are often discovered by the bite marks or eggs on the acropora. Learn more about Acropora Eating Flat Worms.

Acropora Red Bugs

Acropora Red Bugs are very small, red bugs that irritate the acropora colony and lead to less polyp extension. Learn more about Acropora Red Bugs.

Acropora Care Guide - Cheet Sheet

Temperature

• Best Coloration - 73-74F
• Best Growth - 77-79F
• Best Overall - 76-78F

Alkalinity

• Focus on stability, maintaining within 0.5 dKh
• Most success between 7-8 dKh

Calcium

• Focus on stability, within 25ppm.
• 400-450ppm is the ideal range.

Magnesium

• Between 1200-1400ppm. Targeting 1300ppm.

Nitrates and Phosphates

• Nitrates: 1-10ppm
• Phosphates: 0.01 - 0.05ppm

Lighting

• PAR values between 150 and 500 depending on the species.
• Blue and Actinic spectrum are best for color and growth.

Conclusion

This guide will be continuously updated as I learn more about Acropora Care and SPS coral care in general. Hopefully this information will help you be successful with keeping acropora! Happy Reefing!

Additional Coral Care Reading:

• Reef Stable - Acropora Care Guide
• Reef Stable - Montipora Care Guide
• Reef Stable - Euphillia Care Guide
• Reef Stable - Zoanthid Care Guide

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About the Author

John Krenzer

John is a Software Engineer with a passion for saltwater aquariums, as well as the founder and president of Reef Stable. He started in the aquarium hobby as a child with a 20 gallon freshwater aquarium. His interest in aquarium life grew and in 2008, John set up his first saltwater aquarium.

Today, John maintains a 120 gallon mixed reef aquarium as well as a 210 gallon aggressive species aquarium. These large tanks are contained within the same system, sharing a sump as a means to reduce total maintenance and increase total water volume.

John writes articles for the blog as a means to learn about more reef aquarium topics. These articles act as a reference for the readers as well as himself. John updates these articles frequently to provide additional information or make corrections as new information becomes available.

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