How to Raise Barramundi in Aquaponics Systems

January 11, 2025

Among the various fish species suitable for aquaponics, barramundi stands out as one of the top choice for beginners and seasoned aquaponic enthusiasts alike. Known for their hardy nature, fast growth, and delectable taste, barramundi thrive in warm climates and are highly adaptable to aquaponic systems.

They are efficient in converting feed into protein, making them an excellent candidate for anyone looking to maximize yields. Whether you’re planning a backyard setup or a commercial operation, raising barramundi in aquaponics offers a rewarding and sustainable way to grow your own food.

In this blog we will walk you through everything you need to know about successfully raising barramundi in an aquaponic system, from setting up the right environment to managing water quality, feeding schedules, and harvesting your fish.

The Benefits of Raising Barramundi in Aquaponics Systems:

1. Hardy Nature:

Barramundi are resilience, making them ideal for aquaponics beginners. They can tolerate a wide of range of water conditions, including slight fluctuations in pH, temperature, and salinity, as long as these variations are managed carefully.

2. Fast Growth:

Barramundi are fast-growing freshwater and saltwater fish species, and is capable of reaching market size in just 6–8 months under optimal conditions.

3. High Market Value:

Barramundi is prized for its mild, buttery flavor and firm texture, which appeals to a wide range of palates. It’s a favorite in restaurants and supermarkets, commanding a high market price compared to other commonly farmed fish.

Setting Up Your Aquaponics System

Setting up a well-designed aquaponics system is crucial for the successful cultivation of barramundi and healthy plant growth. Below, we’ll explore the common system types, the essential components for a barramundi-friendly setup.

An Overview of Different Types of Aquaponics Systems

1. Media Based Systems:

In media based systems, plants are grown in grow beds filled with a grow media such as clay pebbles orgravel. The grow media provides structural support for the plants and serves as a biofilter, where beneficial bacteria convert fish waste into nutrients for the plants.

Best for: Beginners due to its simplicity and effectiveness. Suitable for growing a variety of plants, including leafy greens, herbs, and fruiting vegetables.

2. Nutrient Film Technique (NFT):

In an NFT system, plants are grown in channels where a thin film of water, rich in nutrients from fish waste, flows continuously along the base of the plants. Their roots are partially submerged in the flowing water to absorb nutrients.

Best for: Smaller plants with shallow root systems, such as lettuce and spinach. It’s less suitable for heavy or large plants.

3. Raft System or Deep Water Culture (DWC):

Also known as raft systems, DWC involves plants floating on a raft above a large body of nutrient-rich water. The plants’ roots are fully submerged, allowing them to absorb nutrients directly.

Best for: Larger systems aiming for high productivity. Ideal for crops like lettuce and basil.

Recommended System:

Media bed systems or the raft system are better suited for barramundi aquaponics because of their ability to handle higher fish loads and provide robust filtration for nutrient-rich water.

Sizing Your System Based on Fish Density

1. Fish-to-Plant Ratio:

A balanced ratio ensures that fish waste production matches the nutrient needs of your plants. A common starting ratio is 1 fish per 20 liters (5 gallons) of water, scaling up as plants grow and consume more nutrients.

2. Tank Volume and Stocking Density:

Barramundi grow rapidly and require adequate space to thrive. Avoid overcrowding, as this can lead to stress, disease, and water quality issues.
For fingerlings: Start with a stocking density of 10–15 fish per 500 liters (130 gallons).
As they grow to harvest size, reduce density to 5–7 fish per 500 liters, or ensure tank upgrades to accommodate their size.

3. Biofiltration Capacity:

The grow bed or biofilter must be large enough to process the fish waste. A good rule of thumb is to match the grow bed volume to the fish tank volume in a media based system.

4. Water Flow Rates:

Ensure the system cycles at least the full tank volume every hour to maintain water quality. Use valves to adjust flow rates for plants and fish as needed.

Choosing and Stocking Barramundi Fingerlings in Your Aquaponics System

Successfully raising barramundi in your aquaponics system starts with sourcing high-quality fingerlings and ensuring they are properly introduced into the system. Careful consideration of stocking densities and acclimation processes is essential for optimal fish health and growth.

Where to Source Quality Fingerlings:

1. Reputable Hatcheries:

Purchase fingerlings from certified hatcheries or aquaculture suppliers to ensure they are disease-free and of high genetic quality.

2. Local Sources:

Check for local fish farms or aquaculture businesses that produce barramundi. Purchasing locally reduces transportation stress and allows you to inspect the stock before purchase.

3. Online Suppliers:

Many aquaculture suppliers offer shipping services for fingerlings. Choose suppliers with good reviews and a guarantee for live delivery.

4. Things to Look For in Quality Fingerlings:

Active and responsive behavior in the water.
No visible signs of disease, such as lesions, abnormal swimming, or discoloration.
Fingerlings of uniform size to reduce competition and aggressive behavior.

Ideal Stocking Densities and Ratios for Barramundi

Stocking density is critical for maintaining fish health and water quality in your aquaponics system. Overcrowding can lead to stress, poor growth, and disease outbreaks, while understocking may result in insufficient nutrient production for plants.

1. Recommended Stocking Densities:

Fingerlings:Start with a stocking density of 15–20 fish per 500 liters (130 gallons) of water.
Grow-Out Stage:As barramundi grow, reduce stocking density to 5–10 fish per 500 liters, depending on their size and tank capacity.

2. Growth Phases and Adjustments:

Fingerlings grow rapidly, often doubling in size within weeks. Regularly monitor their growth and adjust densities to prevent overcrowding.
Consider separating larger and smaller fish into different tanks to avoid competition and cannibalism.

3. Fish-to-Plant Ratio:

Maintain a balanced fish-to-plant ratio for optimal system health. A common rule is 1 kilogram (2.2 pounds) of fish for every 30–40 liters (8–10 gallons) of water once the fish reach full size. Adjust based on plant nutrient requirements.

How to Acclimate Fingerlings to the Aquaponics System

Proper acclimation minimizes stress and ensures the survival of your fingerlings when introducing them to your system.

1. Temperature and Water Quality Matching:

Temperature: The water temperaturein the transportation container and the fish tank should be within 1–2°C (2–3°F) of each other. Use a thermometer to compare and adjust the tank water if necessary.
pH and Salinity: Check and adjust pH and salinity levels to match the conditions in which the fingerlings were raised. A gradual transition is crucial to avoid shock.

2. Acclimation Process:

Float the bag or container with the fingerlings in the fish tank for 15–30 minutes to equalize the water temperature.
Gradually add small amounts of tank water to the container every 5–10 minutes over an hour. This helps the fingerlings adjust to the new water chemistry.
After acclimation, gently release the fingerlings into the tank. Avoid pouring them in forcefully, as this may cause injury or stress.

3. Monitoring After Release:

Observe the fingerlings closely for the first 24–48 hours. Look for signs of stress, such as erratic swimming, lack of appetite, or clustering near the water surface.

4. Feeding After Acclimation

Wait 12–24 hours before offering the first feeding to allow the fingerlings to recover from transport and acclimation.
Start with small amounts of high-quality fingerling feed, and gradually increase the quantity as they begin to feed actively.

How to Feed Barramundi in Aquaponics

Feeding barramundi effectively is crucial for their health, growth, and the overall balance of your aquaponics system. As carnivorous fish, barramundi require high-quality feed tailored to their nutritional needs.

1. Feed Types

Commercial Pellets:

High-protein commercial pellets specifically formulated for carnivorous fish are the best option for barramundi. These pellets provide a balanced diet and ensure consistent growth.
Choose floating or slow-sinking pellets, as these allow you to monitor how much the fish are eating.
Occasionally supplement pellets with live or frozen feed, such as small fish, shrimp, or worms, to mimic their natural diet and enrich their nutrition.
Avoid using wild-caught feed, as it may introduce diseases into the system.

2. Nutritional Requirements

Protein Content:

Fingerlings: 40–50% protein for rapid growth and development.
Grow-out phase: 35–40% protein as they approach harvest size.

Fats and Carbohydrates:

Fats: 10–15% to provide energy and support metabolism.
Carbohydrates: Low levels, as barramundi metabolize protein and fats more efficiently.

Vitamins and Minerals:

Ensure the feed contains essential vitamins (A, D, E, and K) and minerals like calcium and phosphorus to promote strong bone development and overall health.

3.Feeding Schedule

Fingerlings: Feed 3–4 times a day in small amounts to support their high metabolism.
Juveniles and Adults: Feed 1–2 times a day.

Morning feeding: Ensure the fish receive enough energy to stay active throughout the day.
Optional evening feeding: If your fish are growing quickly, a second feeding may be necessary.

Avoid feeding during the cooler parts of the day if the temperature drops significantly, as barramundi are less active in colder water.

How to Manage Water Quality

Maintaining high water qualityis critical for raising healthy barramundi and ensuring the success of your aquaponics system. Water quality directly impacts fish health, plant growth, and the overall stability of the system.

Monitoring Ammonia, Nitrate, and Nitrite Levels

1. Ammonia:

Ammonia is produced as fish waste and uneaten food break down.
High ammonia levels are toxic to barramundi and can stress or kill them.
Safe Range: Less than 0.5 ppm (parts per million).
Beneficial bacteria in the biofilter convert ammonia into nitrites and, subsequently, into less harmful nitrates.

2. Nitrite

Nitrites are an intermediate byproduct of the nitrification process.
Like ammonia, nitrites are toxic and can impair the fish’s ability to transport oxygen in their blood.
Safe Range: Less than 1 ppm.

3. Nitrate

Nitrates are the final product of the nitrogen cycle and are used by plants as nutrients.
While nitrates are less harmful to fish, excessively high levels can still cause stress.
Safe Range: 10–40 ppm for most aquaponics systems. If levels rise above this, increase plant density or conduct partial water changes.

4. Tips for Managing Ammonia, Nitrite, and Nitrate Levels:

Ensure your biofilter is well-established and functioning effectively.
Avoid overfeeding and promptly remove uneaten food.
Stock fish and plants in balanced ratios to match nutrient production with plant uptake.

Regular Water Testing Tools and Tips

1. Essential Water Testing Tools

Water Test Kits: Use aquaponics-specific or aquarium water test kits to measure ammonia, nitrite, nitrate, pH, and other parameters.
Digital Meters: For more precise measurements, invest in digital pH meters, salinity meters, and dissolved oxygen meters.
Thermometers: Use a reliable water thermometer to monitor temperature fluctuations.

2. Water Testing Frequency

Test daily during the initial setup phase or after introducing new fish.
Once the system stabilizes, test water quality weekly.
After significant events like feeding changes or plant harvesting, test again to ensure balance.

3. Record-Keeping

Maintain a log of test results to identify trends and potential issues.
Use the data to adjust feeding schedules, stocking densities, or system components.

The Best Plant Options for Aquaponics with Barramundi

Barramundi are carnivorous fish that produce nutrient-dense waste, making them suitable for a wide range of plants, including leafy greens, herbs, and fruiting plants.

1. Leafy Greens

Lettuce (varieties like romaine, butterhead, and iceberg): Fast-growing and low-maintenance, ideal for beginners.
Spinach: Thrives in aquaponics systems with consistent nutrient availability.
Kale: A hardy and nutrient-dense option that grows well in a variety of conditions.
Swiss Chard: A robust choice that tolerates slight variations in water quality.

2. Herbs

Basil: A popular herb that grows rapidly in aquaponics systems.
Mint: Thrives in water-rich environments and provides a pleasant aroma.
Coriander (Cilantro): A versatile herb that grows well in warm temperatures.
Parsley: A slow-growing herb but excellent for consistent nutrient uptake.

3. Fruiting Plants

Tomatoes: High nutrient demand makes them ideal for mature systems with abundant fish waste.
Peppers (bell peppers, chili peppers): Thrive in the warm environment suited to barramundi.
Cucumbers: Require space to grow but are excellent nutrient consumers.
Strawberries: Adapt well to aquaponics, especially in vertical or tower systems.
Zucchini: A nutrient-hungry plant that complements high fish waste production.

4. Other Options

Legumes (peas and beans): Help replenish nitrogen levels in the water, balancing the system.
Microgreens: Quick-growing and high-value crops that are excellent for small systems.

How to Prevent and Treat Fish Diseases in Aquaponics

Barramundi are generally hardy fish, but like all aquaculture species, they are susceptible to diseases, particularly in environments where water quality fluctuates or if they are stressed.

1. Common Diseases in Barramundi:

Ich: A common parasitic infection, especially in freshwater systems. Symptoms include white cysts on the skin and fins.
Fungal Infections: Often occur when fish are stressed or have injured skin, leading to white, cotton-like growths.
Bacterial Infections: Can cause lesions, ulcers, or swelling. Common bacteria includeVibrio species.
Gill Disease: Infections affecting the gills can result in respiratory problems and decreased oxygen intake.

2. Prevention Strategies:

Maintain Optimal Water Quality: Keep ammonia, nitrite, and nitrate levels within safe ranges, and ensure proper oxygenation and filtration to reduce stress.
Quarantine New Stock: Always quarantine new fish before introducing them to your system to prevent introducing diseases.
Maintain Tank Hygiene: Regularly clean fish tanks and equipment, remove uneaten food, and check for any dead or sick fish.
Natural Remedies: Consider using natural treatments, such as garlic or salt baths, to boost the fish's immune system and treat minor infections.

3. Treatment Options

Medication: For severe bacterial or parasitic infections, use aquaculture-approved medications. Follow the manufacturer's instructions carefully.
Increase Water Aeration: When fish are ill, improve water circulation and oxygen levels to help them recover more quickly.
Isolate Affected Fish: Isolate sick fish to prevent the spread of disease and monitor their condition closely.

How to Manage Temperature Fluctuations

Barramundi are tropical fish, and their health can be greatly affected by temperature changes. Managing temperature fluctuations is essential to keep fish in the optimal environment for growth and health.

1. Challenges with Temperature

Cold Weather: Barramundi thrive in temperatures between 26°C and 30°C (79°F–86°F). In colder water, their metabolism slows, reducing growth rates and making them more susceptible to disease.
Heat Spikes: On the other hand, excessively high temperatures above 32°C (90°F) can stress the fish, lower oxygen levels, and potentially lead to mass die-offs if not addressed.

2. How to Manage Temperature

Use Heaters and Coolers: In systems where temperatures may fluctuate, use a heater or water chiller to maintain a consistent temperature within the ideal range.
Insulation: Insulate tanks to reduce temperature fluctuations caused by external environmental changes.
Shade and Cover: In hot climates, provide shade or use floating covers to keep the water cooler.
Monitor Temperature Regularly: Use digital thermometers or automated systems to track water temperature and ensure it stays within the optimal range.

How to Handle Aggressive or Cannibalistic Behaviors of Barramundi

Barramundi are known to exhibit aggressive behavior, especially when they are overstocked or stressed. This can result in injuries or cannibalism, where larger fish attack smaller ones.

1. Causes of Aggression

Overstocking: Too many fish in a tank can lead to territorial behavior, stress, and competition for food.
Size Differences: When fish are of different sizes, larger fish may dominate smaller ones, leading to bullying or cannibalism.
Water Quality Stress:Poor water quality, such as high ammonia or low oxygen levels, can increase stress and exacerbate aggression.

2. How to Prevent Aggression:

Stocking Density: Avoid overcrowding your fish tank. Ensure you provide ample space for each fish, with a general rule of 5–10 fish per 500 liters (130 gallons) in the grow-out stage.
Size Sorting: Sort and separate fish based on size to prevent larger fish from bullying smaller ones.
Provide Hiding Spots: Use structures like rocks, PVC pipes, or plants to create hiding spots for fish, reducing stress and providing personal space.
Feeding Practices: Feed your fish enough to reduce competition for food. In larger systems, consider using automatic feeders to ensure all fish get their fair share.

3. How to Deal Cannibalism

Remove Injured Fish: If you notice any fish with visible injuries from aggression, remove them promptly and place them in a separate recovery tank.
Ensure a Balanced Diet: Underfed fish are more likely to display aggressive behavior. Provide sufficient high-quality food to satisfy their nutritional needs.

By anticipating and addressing these common challenges, disease management, temperature fluctuations, water quality issues, and aggressive behavior, you can create a more stable and healthy environment for your barramundi and plants.

Conclusion

Raising barramundi in an aquaponics system offers a sustainable and rewarding way to produce both fish and fresh produce. By understanding and addressing key challenges you can create a thriving environment where both fish and plants can flourish. With careful planning, regular monitoring, and the right system components, your aquaponics setup can become a resilient and productive ecosystem.

Are you ready to start your journey in aquaponics with barramundi? Whether you're a seasoned aquaponics enthusiast or a beginner, the insights shared in this guide will help you establish a successful system. Don’t hesitate to dive in—invest in quality equipment, choose the right plant pairings, and always prioritize the health and well-being of your barramundi. Start small, learn along the way, and soon you’ll be harvesting both fish and fresh produce from your very own aquaponics system!