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Acropora Care Guide: The Ultimate SPS Coral for Advanced Reefers

Everything you need to know about keeping Acropora — the undisputed king of SPS corals. From tank maturity and water chemistry to designer varieties and fragging techniques. Compiled from Tidal Gardens, Reef Builders, Bulk Reef Supply, Reef Chasers, Melev’s Reef, Top Shelf Aquatics, and the reef keeping community.

18 min read Sources: 18 expert articles

1. What Makes Acropora Special

Acropora is the undisputed king of SPS (Small Polyp Stony) corals — and arguably the most iconic genus in the entire reef keeping hobby. With over 150 described species, Acropora is the largest genus of reef-building corals on Earth [1]. They are the primary architects of coral reefs worldwide, laying down calcium carbonate skeleton faster than any other stony coral genus [2].

What makes Acropora so captivating is the sheer diversity of growth forms they produce. A single genus gives you staghorn (tall, branching antler-like structures), table (flat, horizontal plates that shade the reef below), bushy (dense, interlocking clusters), and encrusting (low-profile sheets that hug the rock) [1] [3]. This variety means a tank stocked entirely with Acropora can still look wildly diverse in shape, texture, and color.

Acropora are also the fastest-growing stony corals in the hobby. Under optimal conditions, species like A. yongei (the Green Slimer) can add 1–2 inches of new branch growth per month [3]. Their rapid calcification rate is why they demand such pristine water chemistry — they consume calcium, alkalinity, and trace elements at a rate that makes other corals look lazy.

Why “SPS = Stability Promotes Success”: Acropora are the canary in the coal mine of your reef. If your parameters are off, Acropora will be the first to show it. But when conditions are dialed in, nothing rewards you like a thriving Acropora colony. [4]

2. Tank Requirements

Acropora are not beginner corals. They require a mature, established tank — a minimum of 12 months old with stable biological filtration and consistent parameters [2] [5]. Adding Acropora to a new tank is one of the most common mistakes in the hobby. The biological maturity needed goes beyond just cycling; your tank needs established microbial populations, stable dosing routines, and a proven track record of parameter stability [4].

Target Water Parameters

Acropora demand the tightest parameter windows of any coral. Compiled from Reef Chasers [5], Top Shelf Aquatics [4], Tidal Gardens [1], and Extreme Corals [2]:

Parameter Target Range Critical Notes
Alkalinity (dKH) 7.5–8.5 Must be STABLE — daily swing <0.3 dKH [4]
Calcium (ppm) 420–450 Consumed rapidly for skeleton building [5]
Magnesium (ppm) 1350–1400 Prevents CaCO3 precipitation [6]
Nitrate (ppm) 1–5 Too low = brown out; too high = algae [2]
Phosphate (ppm) 0.01–0.03 Ultra-low but not zero [5]
Temperature 76–77°F Lower end of reef range; swings >2°F cause stress [4]
Salinity (SG) 1.025–1.026 35 ppt, stable [5]
pH 8.0–8.3 Higher pH boosts calcification [5]
The #1 Acropora killer is alkalinity instability. A tank with stable 7.8 dKH will dramatically outperform one swinging between 8.0–9.5 dKH. Sudden swings of 3–4+ dKH within 24 hours trigger RTN in most Acropora. [4]

3. Lighting

Acropora are among the most light-hungry corals in the hobby. They rely heavily on their symbiotic zooxanthellae for energy, and intense lighting drives both growth and coloration [7].

PAR Requirements

Most Acropora thrive at PAR 300–500, with placement in the upper third of the tank where light intensity is highest [7] [8]. Some deep-water species (like Oregon Tort) prefer the lower end (250–350 PAR), while shallow-water species like A. millepora can handle 400–500+ PAR once acclimated [7].

300–500
Target PAR range
Upper third of tank [7]
14–20K
Kelvin spectrum
Blue-heavy for color [7]
2–4 wk
Acclimation period
Start low, move up [8]

Spectrum & Photoperiod

Acropora color responds strongly to blue-heavy spectrum in the 14,000K–20,000K range [7]. The blue wavelengths (420–480nm) penetrate deepest in the ocean and are what zooxanthellae have evolved to utilize most efficiently. Many successful Acropora keepers run blue-heavy lighting for 10–12 hours with a shorter 6–8 hour peak white period [7].

Acclimation Protocol

Never place a new Acropora frag at the top of your tank immediately. Start new frags at lower PAR (~180–200) in the middle or lower portion of your rockwork, then gradually move them higher over 2–4 weeks [8]. Sudden exposure to intense light causes bleaching and tissue damage. If using adjustable LED fixtures, you can alternatively reduce intensity by 30–40% and ramp up over the acclimation period [7].

Pro tip: If your Acropora are browning out despite adequate PAR, check your nitrate and phosphate levels. Brown coloration typically indicates elevated nutrients or insufficient light, as the coral produces excess zooxanthellae to compensate. [2]

4. Flow

Acropora evolved on the most wave-exposed sections of coral reefs — they crave water movement. Proper flow keeps tissue clean, prevents detritus from settling in branch crevices, delivers food and dissolved nutrients, and carries away metabolic waste [1] [9].

Turnover Rate

Aim for 40–50x total tank volume turnover per hour for an Acropora-dominant system [9]. Some advanced SPS keepers push to 80–100x, but 40–50x is the sweet spot for most hobbyists [9]. For a 100-gallon tank, that means 4,000–5,000 GPH of total flow.

Flow Characteristics

The type of flow matters as much as the volume. Acropora need random, chaotic, turbulent flow — not laminar blasts from a single powerhead pointed at the colony [9] [10]. Direct laminar flow can damage tissue and prevent polyp extension. Use alternating wavemakers, gyres, or multiple powerheads on opposing walls to create natural, variable wave patterns [10].

Good Flow Setup

  • 2+ wavemakers on opposing walls
  • Random/pulse mode enabled
  • Alternating wave patterns
  • Polyps gently swaying in all directions
  • No dead spots or detritus buildup

Bad Flow Setup

  • Single powerhead blasting one direction
  • Constant laminar flow
  • Polyps pinned flat or unable to extend
  • Detritus settling in branch crevices
  • Dead spots behind rockwork
Signs of inadequate flow: Detritus accumulation between branches, tissue recession at branch bases, brown jelly infections starting in sheltered areas. If you see these, increase flow and improve randomness before anything else. [1]

6. Designer Acropora

The collector coral market has turned certain Acropora morphs into highly sought-after specimens commanding premium prices. These “designer” Acropora are named varieties propagated from a specific mother colony with exceptional coloration [13] [14].

Walt Disney Acropora (A. tenuis)

Growth: Thin branch
Difficulty: Expert
Colors: Rainbow — pink, teal, yellow, purple
Price: $150–$300+

One of the most sought-after rainbow acros ever released — famous for its explosive mix of hot pink corallites, neon yellow and green highlights, electric teal bases, and deep blue-to-purple axial tips. A must-have for any serious acro collector. Requires pristine, ultra-stable conditions to express full coloration. [13]

ORA Hawkins Echinata (A. echinata)

Growth: Open branch
Difficulty: Moderate–Hard
Colors: Orange body, blue/green tips
Price: $50–$100

An ORA aquacultured classic. The contrast between the orange body and electric blue-green growing tips makes it one of the most visually striking echinata morphs. More forgiving than wild tenuis varieties since it’s been captive-propagated for years. [14]

Oregon Tortuosa (A. tortuosa)

Growth: Tight branching
Difficulty: Hard
Colors: Deep sapphire blue
Price: $60–$150

The bluest Acropora in the hobby. Renowned for its intensely saturated, true sapphire-blue coloration that deepens under proper blue-heavy lighting. Slow-growing and demanding — rewards patience with one of the most stunning colors achievable in a reef tank. Prefers lower PAR (250–350) than most Acropora. [14]

Tyree Pink Lemonade (A. sp.)

Growth: Bushy / Clustered
Difficulty: Expert
Colors: Pink base, yellow/lime tips
Price: $100–$250+

A Steve Tyree original — one of the early named designer corals. The contrast between bubblegum pink base tissue and bright yellow-lime growth tips is unmistakable. Slow grower that demands expert-level stability. [13]

Bali Green Slimer (A. yongei)

Growth: Fast staghorn
Difficulty: Moderate
Colors: Vivid neon green
Price: $15–$50

The most accessible “named” Acropora. Gets its name from the green mucus it produces when stressed or handled. One of the fastest-growing Acropora — can add 1–2 inches per month under optimal conditions. Great first Acropora for reefers stepping up from LPS. [3]

Buyer beware: Designer Acropora names are unregulated. There is no certification that a “Walt Disney” frag is genuinely from the original lineage. Buy from reputable vendors with documented chain-of-custody, and expect to pay $50–$300+ for genuine collector pieces. [13]

7. Dosing for Acropora

Acropora are calcium carbonate factories. A healthy colony can consume 1–2 dKH of alkalinity per day in a heavily stocked SPS tank [5]. Without supplementation, your parameters will crash within days. Dosing is not optional — it is essential.

Two-Part Dosing (Minimum)

Two-part solutions (calcium chloride + sodium carbonate) are the entry point for Acropora keeping. They supplement calcium and alkalinity in balanced amounts [15]. Use a dosing pump to deliver small, consistent doses 3–4 times daily rather than one large manual dose — this minimizes parameter swings [4]. Space calcium and alkalinity doses 2–3 hours apart to prevent precipitation [4] [6].

Calcium Reactor (Heavy Systems)

Once your daily two-part consumption exceeds ~100 mL per component, a calcium reactor becomes more practical and cost-effective [15]. Calcium reactors dissolve aragonite media using CO2, providing a steady drip of calcium, alkalinity, and trace elements. They require more setup but offer unmatched stability for large Acropora colonies. Use quality media like ARM or TLF Reborn for trace element replenishment [15].

Supplements

  • Amino acids: Particularly beneficial for Acropora — promote polyp extension, feeding response, and color expression. Dose 2–3x per week. [16]
  • Trace elements: Iodine, strontium, potassium, and iron are consumed by growing colonies. Replenish through water changes with quality salt, or targeted dosing based on ICP-OES testing. Do not blindly dose trace elements — they are “medicine, not food.” [16]
  • Magnesium: Test weekly. If it drops below 1300 ppm, calcium and alkalinity become nearly impossible to maintain. [6]
Testing frequency: Test alkalinity 3x per week minimum in an Acropora tank. Test calcium and magnesium weekly. Consider ICP-OES testing quarterly for a comprehensive trace element snapshot. [4]

8. Fragging Acropora

Acropora are among the easiest corals to frag thanks to their branching growth form. Fragging lets you propagate your colonies, share with fellow reefers, and create “insurance” frags in case the mother colony crashes [17].

1

Choose Your Tool

Use bone cutters (coral cutters) for most Acropora branches — they make clean cuts without crushing the skeleton. For thick branches or table corals, a Dremel with a diamond cutting wheel provides more precision [17]. Curved-blade bone cutters work best for reaching into dense colonies.

2

Cut the Frag

Cut branches 1–2 inches long. Smaller frags have less tissue reserve and take longer to recover; larger frags recover faster but yield fewer pieces. Make clean, decisive cuts — avoid crushing or splintering the skeleton [17]. Cut at a slight angle to maximize glue surface area.

3

Dip in Coral Rx

Dip both the frags and the mother colony in a coral dip (Coral Rx, Revive, or Bayer) for 5–10 minutes [17]. Use a turkey baster to blast between branches. This removes pests (AEFW, red bugs) and promotes healing. Rinse in clean saltwater before returning to the tank.

4

Mount on Plugs

Use reef-safe cyanoacrylate (super glue gel) or a combination of glue and epoxy putty to attach frags to ceramic plugs or rock rubble [17]. Let the glue cure for at least 5 minutes before placing in water. Orient the frag so the growing tip points upward.

5

Recovery

Place frags in a moderate-flow, moderate-light area of the tank. Avoid blasting with direct flow or placing under peak lighting immediately [17]. Expect new tissue growth over the cut areas within 1–2 weeks, with full recovery and visible new branch growth in 4–6 weeks. Do not sell or trade freshly cut frags — wait until tissue has healed over the frag plug [17].

Fraggging hygiene: Sterilize your bone cutters between colonies with rubbing alcohol or fresh saltwater. Cross-contamination can spread pests and pathogens between corals. [17]

9. Common Problems

RTN (Rapid Tissue Necrosis)

Cause: Sudden parameter swings — especially alkalinity shifts of 3+ dKH within 24 hours, temperature spikes, or salinity changes. Bacterial infection often follows the initial stress event. Tissue peels off the skeleton in hours, typically starting from the base [4] [18].

Fix: Immediately frag any surviving branches at least ½ inch ahead of the receding tissue line. Dip rescued frags in Coral Rx. Identify and correct the parameter shift that triggered the event. RTN is usually fatal for the affected colony but frags can survive [18].

STN (Slow Tissue Necrosis)

Cause: Chronic low-level stress — gradual alkalinity drift, low nutrients (near-zero nitrate/phosphate), insufficient flow causing detritus accumulation, or slow parameter creep over weeks. Tissue slowly recedes from the base upward, exposing white skeleton that quickly gets colonized by algae [4] [18].

Fix: Test all parameters and identify what has drifted. Increase feeding to raise nutrients if NO3 and PO4 are bottomed out. Improve flow around the affected colony. Frag healthy branches as insurance. STN is reversible if caught early [18].

AEFW (Acropora Eating Flatworms)

Cause: Tiny brown/clear flatworms (Amakusaplana acroporae) that feed on Acropora tissue. Nearly invisible to the naked eye. They leave bite marks and egg clusters on the coral skeleton. Infested corals turn brown and lose tissue [18].

Fix: Remove the coral and dip in Coral Rx or Bayer insecticide (10 mL per gallon) for 5–10 minutes. Blast between branches with a turkey baster to dislodge flatworms and eggs. Repeat every 4–7 days for at least 3 treatments, as eggs are resistant to dips. Quarantine all new Acropora additions [18].

Brown Out

Cause: Excess zooxanthellae production due to elevated nutrients (high nitrate/phosphate) or insufficient lighting. The coral appears dull brown instead of vibrant colors [2].

Fix: Reduce feeding, increase GFO/carbon usage to lower nutrients, and verify PAR levels at the coral’s location. Increase lighting gradually if PAR is below 250. Color should return over 2–4 weeks as nutrients drop and zooxanthellae density normalizes [2].

Bleaching

Cause: Expulsion of zooxanthellae due to extreme stress — temperature spike above 82°F, sudden light increase, or chemical contamination. Coral turns white or pale, losing its primary energy source [2] [8].

Fix: Move to lower light and flow area. Correct the triggering stressor (temperature, lighting). Feed amino acids and small-particle foods to provide alternative energy. Bleached Acropora can recover if the stress is removed quickly, but prolonged bleaching (2+ weeks) is usually fatal [2].

Tips Burning (White Tips)

Cause: Alkalinity swings or a mismatch between alkalinity and nutrient levels. When alkalinity is too high relative to available nutrients, the fast-growing tips calcify faster than tissue can keep up, leaving exposed white skeleton at the tips [4].

Fix: Verify alkalinity stability (test daily for a week). If alk is stable but tips are still burning, slightly increase feeding to raise nutrients. Ensure nitrate is at least 1–2 ppm and phosphate is 0.01+ ppm. The balance between alkalinity and nutrients is key [4].

10. Frequently Asked Questions

How long should my tank be running before adding Acropora?

A minimum of 12 months is the widely recommended timeframe [2] [5]. Your tank needs established biological filtration, stable dosing routines, and a proven track record of consistent parameters. Some experienced reefers add hardy species like A. yongei at 6–9 months, but this is risky for beginners. Start with easier SPS like Montipora before attempting Acropora [1].

What is the easiest Acropora for beginners?

Acropora yongei (Green Slimer) and A. nasuta are the most forgiving species [1] [3]. Both tolerate slightly wider parameter ranges, grow fast enough to recover from minor issues, and are widely available at affordable prices ($15–$40). Aquacultured frags (like those from ORA) are also easier than wild-collected specimens because they are already adapted to aquarium conditions.

Why are my Acropora turning brown?

Brown coloration means the coral is producing excess zooxanthellae, which masks the coral’s natural pigments. This is typically caused by elevated nutrients (nitrate >10 ppm or phosphate >0.05 ppm) or insufficient lighting (PAR below 200) [2]. Lower nutrients with GFO and carbon, increase PAR gradually, and color should return over 2–4 weeks. Also check for AEFW, which can cause browning as the coral becomes stressed [18].

Can Acropora touch each other?

Different species should not touch. Acropora engage in “coral warfare” — when branches from different species make contact, one will typically sting and kill the tissue of the other [1]. Same-species colonies can sometimes fuse together, but it is not guaranteed. Always leave at least 2–3 inches of growth room between different Acropora colonies to account for future growth.

Do Acropora need to be fed?

Acropora get most of their energy (85–95%) from photosynthesis via their zooxanthellae [1]. However, supplemental feeding — particularly amino acids and small-particle coral foods — can significantly boost growth rate and color expression [16]. Broadcast feed 2–3 times per week with the return pump off for 15 minutes. Avoid overfeeding, which raises nutrients.

How fast do Acropora grow?

Growth rate varies dramatically by species and conditions. Fast growers like A. yongei (Green Slimer) can add 1–2 inches per month of new branch growth [3]. Moderate growers like A. millepora average 0.5–1 inch per month. Slow growers like Oregon Tort may only add 0.25–0.5 inches monthly. Optimal conditions (stable alk, high PAR, strong flow, amino acid supplementation) maximize growth across all species [1].

References

Every factual claim in this guide is cited to its original source. Click any [n] in the text above to jump here.

  1. Tidal Gardens — “Acropora Coral Care”
  2. Extreme Corals — “Care Requirements of Acropora in Home Reef Aquariums”
  3. Extreme Corals — “Exploring The Most Popular Types Of Acropora”
  4. Top Shelf Aquatics — “SPS Coral Stability: The Complete Guide to Maintaining Consistent Parameters”
  5. Reef Chasers — “Coral Care Guide: Acropora Corals”
  6. Reefs.com — “Aquarium Chemistry: Magnesium In Reef Aquaria”
  7. Top Shelf Aquatics — “SPS Coral Lighting: PAR, Spectrum, and Photoperiod Explained”
  8. Reef Chasers — “Coral Lighting Care Guide”
  9. Reef Tank Resource — “How Much Flow In A Reef Tank (Guide)”
  10. Reef Builders — “Frequently Asked Questions on Wavemakers” (2023)
  11. ReefBum — “SPS Deep Dive: Acropora millepora”
  12. Reeflings — “Acropora: Complete Overview & Care Guides”
  13. Cultivated Reef — Designer Acropora listings + TSM Aquatics — Walt Disney Acropora
  14. ORA (Oceans, Reefs & Aquariums) — Oregon Tortuosa + Top Shelf Aquatics — OG Oregon Tort
  15. Reef2Reef — “Switching to Calcium Reactor from Dosing 2 Part” + community dosing threads
  16. Manta Systems — “Amino Acid, Carb & Vitamin Dosing in Reef Tanks” + “Beyond the Big Three: Trace Elements”
  17. Bulk Reef Supply — “Top 12 Tips for Fragging SPS Corals” + Sunnyside Corals — “How To Frag Acropora”
  18. Bulk Reef Supply — “Coral Tissue Necrosis: The Mystery of RTN and STN” + Melev’s Reef — “Acropora Eating Flat Worms (AEFW)”

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