Are you after an SPS (small polyp stony) dominated aquarium, but are unsure what Acropora (Acro) Corals will create that mini coral reef the quickest?
Not only are Acropora Corals the most common SPS coral found on coral reefs, but they are also one of the most popular SPS corals in reef tanks, and when you see them in an aquarium, you will see why they are often called the “crown jewels”!
Even though SPS corals like Acropora are more challenging to care for, their fast growth is what attracts reefers – from beginner hobbyists to coral experts, and everyone in between! The one question all reef hobbyists have in common, is their interest in Acro growth rates, a question that we are here to shed some light on.
How Fast Does Acropora Grow?
Let’s jump straight into the “million-dollar” question among Acropora enthusiasts, and one you have probably been asking ever since you got your hands on your Acropora frag – how fast does Acropora grow?
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”.
A recent study (2020) on Acropora growth in Puerto Rico looked at the average growth rate of two Staghorn Corals:
- Acropora cervicornis: 37.2 cm/year
- Acropora prolifera: 31.2 cm/year
The lack of scientific research on Acropora growth rates makes it difficult for hobbyists like yourself, so why not make your own mini-study and measure the growth of your Acro over time!
How Long Does It Take For Acropora To Grow?
Like any other coral species, Acros need time to acclimate to reach their full potential. This can take anywhere between 6 months to 2 years for an Acropora to fully establish and grow.
How To Grow Acropora Fast?
While there is no magic wand you can swing to make your Acropora Corals grow fast, there are 8 key factors to successfully growing Acropora Corals.
1. Patience & Tank Stability
Patience and stability are two of the most important factors to becoming a successful aquarium hobbyist. Keeping your water parameters within the acceptable ranges and giving your Acro time to settle into their new home will help your coral get off on the right foot. This does, however, take time, so patience is extremely critical during this time.
2. Providing Appropriate Lighting
Many reef hobbyists swear by LED-only lighting, and while they are great lighting fixtures for most corals, Acropora Corals can be a little “old-school”. Acropora Corals prefer to grow under metal halide, or LED and metal halide hybrid lighting fixtures. While it may cost you a bit more on your electricity bill, with the correct light intensity (moderate to high) and PAR level, metal halides are the best lighting to grow Acroporas fast.
A PAR level of 250-500 is recommended. Some Acro species can tolerate levels up to 750 PAR, however, always check the specific lighting requirements of your particular Acro before turning up the light intensity. To monitor your lighting levels, it is recommended to buy a PAR meter.
3. Increasing The Water Flow
Moderate to strong water movement with a random flow is recommended to successfully grow Acropora. Not all Acros will thrive with high flow conditions, however, if you notice their growth is very slow, consider increasing the flow.
4. Running Slightly Higher pH Levels
Coral calcification is a measure of coral growth, which is linked to pH. Now, we know it can be difficult to maintain pH levels as most aquariums have diurnal swings, but try to get your pH level as close to 8.5 during the day so the overnight low doesn’t drop too low. Acropora Corals require a pH range between 7.8 and 8.2 to maintain healthy and rapid growth and undergo calcification.
5. Mounting Your Frag Sideways
Acropora love to be mounted either sideways or diagonally on the edge of rocks. This position maximizes the amount of lighting your Acro will receive, facilitating their growth.
If you have ever been lucky enough to go snorkeling or scuba diving, you will notice that corals grow in all directions, therefore, mounting your Acro sideways will also give your aquarium a more natural look.
6. Regular Water Changes
You are probably already doing this, but more frequent water changes will help your Acro grow faster. When you perform a water change, you replenish lost trace elements and nutrients, both of which are important for healthy and fast growth.
To grow Acropora fast, it is recommended to perform a 15% water change at least every 2 weeks, and dose your aquarium with trace elements (calcium, magnesium, and alkalinity).
7. Fragging Your Coral
Fragging is the manual cutting of branches from a Coral. Cutting branches off the main fragment of your Acropora Coral can often stimulate new growth if it is a healthy specimen.
If you do decide on fragging your Acropora Coral, make sure it is growing and thriving well inside the aquarium before you grab your pair of pliers!
8. Moving Your Acro Coral
While it can be a pain to rearrange your corals, if your Acro is not growing at all over a long period, you should consider moving it to an area with more lighting or flow, making sure you do not blast them in the process as this will stunt their growth.
Moving your Acro may just help find its sweet spot!
Fastest Growing Acropora
You should always aim to buy Acropora Corals from local reefers or LFS (local fish stores) that have a positive history of captive growth, aquarium stability, and hardy corals. This will increase the chances of your Acro having healthy and rapid growth.
If you are looking for some fast-growing Acropora Corals, try these:
- Bali Green Slimer Acro
- Red Planet Acro
- Homewrecker Acro
- Pink Lemonade Acro
- PC Rainbow Acro
Conclusion
Acropora Corals grow at different rates depending on the species you have, however, growth greater than 15 cm/year is considered very good with aquarium-kept corals.
To grow your Acropora to its maximum potential, proper acclimation is required before adding it to your aquarium. After you have added your “crown jewels” to your aquarium, you can try a few things to increase growth rates such as, increasing water flow, mounting your Acro sideways, and maintaining tank stability. For more information on Acropora growth, check out our ultimate Acropora coral care guide!
