𝐀𝐦𝐢𝐧𝐨 𝐀𝐜𝐢𝐝, 𝐂𝐚𝐫𝐛𝐨𝐡𝐲𝐝𝐫𝐚𝐭𝐞, 𝐚𝐧𝐝 𝐕𝐢𝐭𝐚𝐦𝐢𝐧 𝐃𝐨𝐬𝐢𝐧𝐠 𝐢𝐧 𝐑𝐞𝐞𝐟 𝐓𝐚𝐧𝐤𝐬: 𝐔𝐧𝐝𝐞𝐫𝐬𝐭𝐚𝐧𝐝𝐢𝐧𝐠 𝐓𝐡𝐞𝐢𝐫 𝐑𝐨𝐥𝐞𝐬 𝐚𝐧𝐝 𝐁𝐞𝐧𝐞𝐟𝐢𝐭𝐬

Introduction

Reef aquariums are delicate ecosystems where corals rely on a finely balanced mix of light, nutrients, and dissolved organic compounds to thrive. While much attention is given to calcium, alkalinity, and trace elements, another crucial aspect of coral health is often overlooked—organic supplementation.

Amino acids, carbohydrates, and vitamins are increasingly used in reef aquaria to enhance coral growth, coloration, tissue repair, and feeding response. But are they truly necessary? And if so, what’s the best way to dose them without causing unwanted side effects like bacterial blooms or cyanobacteria outbreaks?

In this article, we’ll break down the scientific role of these supplements, explore how different corals utilize them, and outline tank-specific dosing strategies to help you make informed decisions. Whether you're running an SPS-dominant ultra-low nutrient system (ULNS) or a mixed reef with LPS and soft corals, understanding how and when to dose these organic compounds can make a significant difference in coral health and reef stability.

Let's dive into the science behind amino acids, carbohydrates, and vitamins—what they do, how corals absorb them, and how to integrate them into your reefing routine effectively.

What Are Amino Acids, and Why Do Corals Need Them?

Amino acids are the building blocks of proteins, and corals require them for tissue growth, enzyme production, and overall metabolic functions. In the wild, corals obtain amino acids through:

• Zooplankton consumption (e.g., copepods, rotifers)
• Absorption from the water column (dissolved organic matter)
• Symbiotic relationships (coral-algae nutrient cycling)

Most reef tanks already supply amino acids in some form, whether through fish waste, feeding, or bacterial activity.

Potential Benefits of Amino Acid Dosing

Amino dosing is often marketed as beneficial for:

1. Coloration Enhancement – Certain amino acids can boost pigmentation by supporting metabolic processes related to chromoprotein expression.
2. Tissue Repair & Growth – Corals recovering from fragging, stress, or disease may benefit from additional amino acids.
3. Increased Polyp Extension – Some reefers report more pronounced feeding responses.
4. Nutrient Uptake Support – Some amino formulations are designed to help corals utilize nitrates and phosphates more efficiently.

Potential Downsides & Risks

• Excess Nutrients → Algae & Cyanobacteria Blooms – Overdosing can lead to bacterial overgrowth, fueling unwanted algae.
• Variable Coral Response – Some corals react positively, while others show little to no difference.
• Quality of Additive Matters – Some commercial amino blends contain unnecessary fillers that can contribute to unwanted organics.

Key Amino Acids in Coral Dosing & Their Effects

Corals require various amino acids for metabolic functions, including tissue repair, coloration, and growth. While corals can absorb dissolved amino acids from the water, not all amino acids function the same way.

1. Glutamine & Glutamic Acid

• Function: Supports tissue growth, cell repair, and immune function.
• Best for: Corals recovering from fragging or stress, fast-growing SPS.
• Notes: Naturally produced by many marine organisms, but supplementation can help in ultra-low nutrient systems (ULNS).

2. Aspartic Acid

• Function: Plays a major role in coral skeletal growth and calcification.
• Best for: SPS corals (Acropora, Montipora, etc.), LPS with strong skeletal structure.
• Notes: Works synergistically with calcium and alkalinity dosing.

3. Glycine

• Function: Involved in protein synthesis, helps in polyp extension and feeding response.
• Best for: Polyp-heavy corals like Goniopora, Zoanthids, and soft corals.
• Notes: Often included in amino blends to support overall tissue health.

4. Alanine

• Function: Energy metabolism and nitrogen balance in coral tissues.
• Best for: Corals in low-nutrient tanks that need additional energy sources.
• Notes: Helps corals process excess nitrogen efficiently.

5. Leucine, Isoleucine & Valine (Branched-Chain Amino Acids - BCAAs)

• Function: Critical for protein synthesis and muscle tissue formation in fish, but also supports coral growth.
• Best for: SPS corals that require rapid tissue growth.
• Notes: Helps maintain coral tissue mass under stress conditions.

6. Serine & Threonine

• Function: Supports mucus production, tissue healing, and immune response.
• Best for: LPS corals like Euphyllia and Acanthastrea that produce large amounts of mucus.
• Notes: Often included in amino products for general coral health.

7. Proline & Hydroxyproline

• Function: Essential for collagen production and structural integrity in coral tissue.
• Best for: Soft corals, LPS, and any coral needing stronger tissue resilience.
• Notes: Helps corals maintain elasticity and avoid tissue necrosis.

8. Arginine

• Function: Boosts cellular growth and supports nitrogen metabolism.
• Best for: Rapid-growing corals like Montipora and Acropora.
• Notes: Sometimes included in formulations designed for stressed or recovering corals.

How These Amino Acids Work Together

While individual amino acids have their own benefits, they often work best in combination. Many commercial amino acid supplements are formulated with a mix to target multiple coral functions, such as:

• Growth-focused blends – High in aspartic acid, arginine, and glutamine for strong skeletal structure and tissue repair.
• Coloration-focused blends – Include BCAAs, glycine, and proline to enhance pigmentation and polyp extension.
• General maintenance blends – Contain serine, threonine, and hydroxyproline to improve tissue resilience and immune response.

Do All Corals Benefit from Amino Acid Dosing?

• SPS corals (Acropora, Montipora, etc.) – Yes, especially in ULNS tanks where nutrients are low.
• LPS corals (Euphyllia, Acanthastrea, etc.) – Beneficial, particularly for tissue repair after fragging.
• Soft corals (Zoanthids, Goniopora, etc.) – Moderate benefits, especially in high-flow environments.
• NPS corals (Sun Corals, Dendrophyllia, etc.) – Less important since they rely more on direct feeding.

Comparing Different Amino Acid Additives

Here’s a look at a few common brands and their differences:

*The Two Little Fishes link is to Bulk Reef Supply as they have the most information on the product.*

Key Takeaways

• SPS-dominant tanks (ULNS): Korallen-Zucht, Aquaforest, Brightwell CoralAmino, AcroPower
• LPS-dominant tanks: Boyd Vitachem, Red Sea Reef Energy AB+, Fauna Marin Ultra Amin
• Mixed reefs: Seachem Reef Plus, Polyp Lab Polyp-Booster, Brightwell CoralAmino
• Coral frag recovery and tissue repair: Brightwell CoralAmino, Boyd Vitachem, Seachem Reef Plus
• Coral feeding stimulation: Polyp Lab Polyp-Booster, Red Sea Reef Energy AB+

Considerations:

• Disclosure Variability: Many manufacturers do not provide detailed compositions of their amino acid supplements, making direct comparisons challenging.

• System Specificity: The effectiveness of a supplement can vary based on the specific needs of your reef system, including coral types, existing nutrient levels, and overall husbandry practices.

• User Experiences: Anecdotal evidence from reefing communities can offer insights into product performance, but individual results may vary.

Given the proprietary nature of these formulations, it's advisable to monitor your corals' responses when introducing a new supplement and adjust dosing as needed. Always start with the manufacturer's recommended dosage and observe for any changes in coral health and coloration.

Who Should Consider Amino Dosing?

• SPS-dominant tanks – Since SPS corals rely more on dissolved organics, amino acids may provide a noticeable benefit.
• Ultra-low nutrient tanks (ULNS) – When NO₃ and PO₄ are extremely low, corals can lack sufficient organic material for metabolism.
• Corals recovering from fragging or stress – Supplemental amino acids may speed up tissue regeneration.

Who Might Not Need It?

• Mixed reef tanks with regular feeding – If you’re already feeding fish, corals, and using quality foods, additional aminos may not be necessary.
• High-nutrient systems – If NO₃ and PO₄ are already present in good levels, adding aminos could push nutrient levels too high.

Why Are Carbohydrates Added to Some Amino Acid Blends?

Carbohydrates serve as an alternative energy source for corals and their symbiotic zooxanthellae. Corals rely on photosynthesis, dissolved organic matter, and particulate feeding for energy, but in nutrient-stripped systems, supplemental carbohydrates can help sustain their metabolic processes.

Key Reasons for Carbohydrate Inclusion:

1. Energy Boost for Corals – Corals, particularly SPS, require a steady energy supply for growth, mucus production, and immune response. Carbohydrates provide a direct source of energy that can enhance metabolic function.
2. Supports Zooxanthellae Activity – The symbiotic algae inside corals (zooxanthellae) primarily use light to produce energy, but additional organic carbon sources can help sustain them in low-nutrient environments.
3. Enhances Coral Coloration – Carbohydrate supplementation can influence chromoprotein production, enhancing coral pigmentation.
4. Encourages Polyp Extension and Feeding Response – Some corals exhibit an enhanced feeding response when exposed to dissolved organic carbon sources.
5. Prevents Starvation in ULNS Tanks – In tanks where nitrate and phosphate are undetectable, corals may struggle to obtain enough organic material, leading to pale or starving corals. Carbohydrates help mitigate this risk.

Common Carbohydrates Found in Coral Supplements:

• Glucose – A simple sugar used for direct energy production.
• Sucrose – Another sugar that corals can metabolize.
• Ethanol (carbon source) – Found in some dosing regimens (e.g., carbon dosing methods like Vodka or Red Sea NO3:PO4-X) to encourage bacterial growth, which corals can consume.
• Other Polysaccharides – Included in some blends to support microbial diversity in the tank.

Potential Drawbacks:

• Overuse of carbohydrates can lead to bacterial blooms, which may deplete oxygen levels and fuel unwanted algae or cyanobacteria.
• Some ULNS tanks may become unstable if too much dissolved organic carbon is introduced.

Why Are Vitamins Included in Some Amino Acid Blends?

Corals, like other animals, require micronutrients to regulate metabolic functions. Many commercial amino acid blends include vitamins to support overall coral health, growth, and coloration.

Key Reasons for Vitamin Inclusion:

1. Boosts Coral Immune Function – Vitamins help corals resist stress from environmental changes, pathogens, or fragging.
2. Enhances Tissue Growth & Repair – Vitamins play a role in collagen formation and cell division, helping corals recover from damage.
3. Supports Zooxanthellae Health – Some vitamins are critical for photosynthetic efficiency in symbiotic algae.
4. Improves Coloration – Vitamins influence pigment production and oxidative stress responses, which can help corals maintain vibrant colors.

Common Vitamins Found in Coral Supplements:

• Vitamin C (Ascorbic Acid) – A powerful antioxidant that supports coral tissue repair and immune defense.
• Vitamin B Complex (B1, B2, B3, B5, B12, etc.) – Helps in energy metabolism, enzyme function, and cell regeneration.
• Vitamin E (Tocopherol) – Acts as an antioxidant, protecting coral cells from oxidative stress.
• Vitamin D – Less commonly included but may aid in calcium regulation and skeletal growth.

Potential Drawbacks:

• Excess vitamin supplementation may not always be necessary in well-fed systems.
• Some vitamins degrade quickly in water, making dosing frequency an important consideration.

Which Corals Benefit the Most from Carbohydrates and Vitamins?

• SPS Corals (Acropora, Montipora, etc.) – High-energy corals that benefit from additional carbohydrate availability in ULNS tanks.
• LPS Corals (Euphyllia, Acanthastrea, etc.) – Benefit from vitamins that support tissue health and repair.
• Non-Photosynthetic (NPS) Corals (Dendrophyllia, Tubastrea, etc.) – May benefit from carbohydrate-rich diets since they do not rely on light for energy.
• Soft Corals (Zoanthids, Goniopora, etc.) – Often show improved feeding responses when carbohydrates are included in dosing regimens.

Is Carbohydrate Dosing and Carbon Dosing the same?

Carbohydrate dosing and carbon dosing are related but serve different purposes in a reef aquarium. While both involve adding organic carbon sources to the tank, their effects on corals, microbial populations, and nutrient balance are distinct.

Carbohydrate VS. Carbon Dosing

Carbohydrate Dosing Explained

• Carbohydrates are used as an energy source for corals and beneficial bacteria.
• Some amino acid blends include carbohydrates to mimic natural dissolved organic matter (DOM) in the ocean.
• Used primarily in ultra-low nutrient systems (ULNS) to prevent corals from starving.
• Can enhance coloration and polyp extension but should be used sparingly to avoid fueling unwanted bacterial or cyanobacterial growth.

Carbon Dosing Explained

• Carbon dosing is a method for nitrate and phosphate control.
• It stimulates bacterial growth, and as the bacteria multiply, they consume excess NO₃ and PO₄.
• The increased bacterial biomass is then removed via protein skimming or consumed by filter feeders.
• Popular in reef tanks struggling with high nutrients but should be monitored to avoid bacterial overgrowth.

Can You Use Both?

Yes, but carefully.

• If running an ultra-low nutrient system (ULNS), small amounts of carbohydrate dosing can help coral energy metabolism, while carbon dosing keeps NO₃ and PO₄ in check.
• However, dosing too much of either can fuel bacteria or cyanobacteria in unintended ways.

Dosing Strategies by Tank Type

1. Ultra-Low Nutrient Systems (ULNS) – SPS-Dominant Tanks

• Characteristics:

  • High filtration efficiency (e.g., heavy skimming, zeovit, carbon dosing)
  • Nitrate and phosphate often undetectable
  • High light, high flow

• Dosing Strategy:

  • Amino Acids: Dose daily to compensate for the lack of dissolved organics.
    • Focus on aspartic acid, glutamine, BCAAs to support skeletal growth and tissue formation.
  • Carbohydrates: Use a controlled amount to maintain microbial balance and energy availability for corals.
    • Best practice: Small, frequent doses (e.g., every other day) to avoid fueling cyanobacteria.
  • Vitamins: Supplement weekly or bi-weekly, depending on coral response.
    • Vitamin C and B-complex vitamins are beneficial to prevent oxidative stress from high-light exposure.

• Scientific Rationale:

  • SPS corals absorb amino acids directly from water and have higher metabolic demands, so consistent dosing prevents starvation.
  • Excessive carbohydrate dosing can disrupt bacterial equilibrium, leading to bacterial blooms or cyanobacteria outbreaks.

2. Mixed Reef Tanks (SPS, LPS, Soft Corals)

• Characteristics:

  • Moderate nutrients (nitrate 2-10 ppm, phosphate 0.02-0.1 ppm)
  • Balanced feeding (fish contribute to nutrient load)
  • Moderate to high light and flow

• Dosing Strategy:

  • Amino Acids: Dose 3-5 times per week, adjusting based on coral response.
    • Include glycine, glutamine, and proline for general tissue health.
  • Carbohydrates: Usually not necessary unless running an aggressive nutrient export method.
    • If needed, dose twice weekly in small amounts to maintain microbial diversity.
  • Vitamins: Dose weekly, especially if running activated carbon or heavy skimming, which can remove dissolved organics.

• Scientific Rationale:

  • A mixed reef benefits from intermittent dosing, as LPS corals do not rely on dissolved amino acids as heavily as SPS corals.
  • Regular fish feeding contributes to natural amino acids and organic carbon levels, so excessive dosing can lead to algae blooms.

3. LPS-Dominant Tanks

• Characteristics:

  • Higher nutrient levels (nitrate 5-20 ppm, phosphate 0.05-0.2 ppm)
  • Low to moderate flow
  • Moderate light

• Dosing Strategy:

  • Amino Acids: Dose twice per week, focusing on serine, threonine, and glycine, which support mucus production and polyp extension.
  • Carbohydrates: Not usually necessary, as LPS corals rely more on direct feeding than dissolved organic carbon.
  • Vitamins: Dose weekly, particularly vitamin C to aid in tissue recovery after fragging.

• Scientific Rationale:

  • LPS corals primarily capture food rather than absorbing dissolved nutrients, so amino acid dosing is less critical than in SPS tanks.
  • Occasional dosing can enhance tissue health and feeding response without increasing the risk of bacterial blooms.

4. Soft Coral & Zoanthid Tanks

• Characteristics:

  • Higher tolerance for nutrients (nitrate 10-30 ppm, phosphate 0.1-0.3 ppm)
  • Low to moderate flow
  • Low to moderate light

• Dosing Strategy:

  • Amino Acids: Dose once or twice per week, focusing on glycine and proline to promote polyp extension and tissue growth.
  • Carbohydrates: Minimal to no dosing needed.
  • Vitamins: Dose bi-weekly to support overall coral health.

• Scientific Rationale:

  • Soft corals and zoanthids thrive in higher nutrient environments and do not require aggressive amino acid supplementation.
  • Intermittent dosing can help with tissue growth but is not as essential as in SPS-dominant systems.

5. Non-Photosynthetic (NPS) Coral Tanks

• Characteristics:

  • No reliance on light (Tubastrea, Dendrophyllia, Gorgonians, etc.)
  • Heavy feeding required (meaty foods, plankton, liquid foods)
  • Low to moderate flow

• Dosing Strategy:

  • Amino Acids: Dose daily to mimic natural organic availability in deep-sea environments.
  • Carbohydrates: Dose moderately, as some NPS corals can metabolize dissolved organic carbon.
  • Vitamins: Dose weekly to replenish nutrients lost to filtration.

• Scientific Rationale:

  • Since NPS corals do not rely on photosynthesis, amino acids and carbohydrates help sustain them when live feedings are insufficient.
  • Vitamin supplementation can improve nutritional uptake and immune response.

Advanced Considerations for Dosing

• Observe Coral Response – Polyp extension, growth, and coloration changes can indicate whether dosing is beneficial.
• Adjust Based on Nutrient Levels – If nitrate and phosphate rise unexpectedly, consider reducing carbohydrate or amino acid dosing.
• Dose at Night for Maximum Absorption – Many corals absorb amino acids more efficiently at night when their polyps are extended.
• Avoid Overdosing – Excessive amino acid or carbohydrate dosing can lead to bacterial blooms, cyanobacteria outbreaks, or unwanted algae growth.

Final Verdict: Universal Advantage?

There isn’t a one-size-fits-all answer. The benefits of amino dosing are context-dependent. In nutrient-limited tanks, aminos can be a game-changer. In well-fed systems, they might be redundant—or even problematic. Like any additive, careful observation and controlled testing are key to seeing whether amino dosing truly benefits your specific setup.

Happy Reefing!

References:

1. Riddle, D. (2015). Coral Nutrition, Part Three: Amino Acids, Proteins, and Carbs. 

   • Available online: Reefs.com

2. Ferrier-Pagès, C., et al. (2011). Physiological response of scleractinian corals to nutrient enrichment. Journal of Experimental Marine Biology and Ecology, 408(1-2), 201-209.

3. Shinzato, C., et al. (2011). Using the Acropora digitifera genome to understand coral responses to environmental change. Nature, 476(7360), 320-323.

4. Borneman, E. H. (2001). Aquarium Corals: Selection, Husbandry, and Natural History. TFH Publications.

5. Delbeek, J. C., & Sprung, J. (2005). The Reef Aquarium: Science, Art, and Technology, Vol. 3. Ricordea Publishing.