The Best Cold-Water Fish for Aquaponics Systems

Central to the success of aquaponics systems is the selection of appropriate fish species, which plays a crucial role in nutrient cycling and system stability. While warm water fish like tilapia and catfish are commonly used in aquaponics, cold water fish present a viable alternative for regions with cooler climates or specific environmental conditions. 

Cold water fish species not only thrive in lower water temperatures but also offer unique advantages in terms of growth rates, feed efficiency, and environmental adaptability within aquaponics setups. 

This blog will explore some of the best cold-water fish species suited for aquaponics systems, highlighting their characteristics, benefits, and considerations for successful integration into sustainable aquaponics practices.

Aquaponics in Colder Climates

Most aquaponics systems are built in a tropical environment, making warm water fish like tilapia a popular choice for fish. But that doesn't mean that people living in colder climates cannot practice this sustainable growing method.

Aquaponics can be built even in colder climates and the key to its success is choosing the right fish and plants to grow. Choose fish that thrive in colder water. Most cold-water fish species can do well at a temperature of less than 50°F.

Challenges of Cold Water Aquaponics

The best thing about having cold-water fish in your fish tanks is that you don't need to install heaters since your fish enjoy the cold waters. The real challenge is when the weather is freezing. Once the water freezes, your fish will become sluggish, and your plants will also experience stunted growth. Your pipes could also freeze, which will need heaters to heat up the temperature into an acceptable range, or you might need to install pipes insulation. 

You will also have limited options on what plants to cultivate. It will contribute to the success of your system if you choose plants that thrive in cold weather, such as winter-hardy varieties of leafy greens like swiss chard, kale, lettuce, and sage. 

However, despite the challenges mentioned above, aquaponics in cold water can be successful, especially if you grow indoors or in a greenhouse where you can control the environment. 

Advantages and Disadvantages of Raising Cold Water Fish in Colder Climates

Advantages of Cold-Water Fish:

1. Cold-water fish are more tolerant of fluctuating water temperatures than tropical fish. This means that they can better withstand the colder winters in many parts of the country. If your system experiences a power outage or the temperature drops suddenly, your fish are less likely to be affected than if you raised tropical fish.
2. Another advantage of cold-water fish is that they grow more slowly than tropical fish. The slower growth rate means that the fish will produce less waste, which will make your system more efficient and reduce the amount of work required to maintain it. This may not sound like an advantage, but it actually is.
3. Cold-water fish are also more resistant to diseases and parasites, making them a healthier option for your system.

Disadvantages of Cold-Water Fish:

1. Cold-water fish grow more slowly than tropical fish, which can be frustrating if you are hoping to harvest fish quickly.
2. Cold-water fish produce less waste than tropical fish, so your system may not be as efficient if you are raising cold-water fish.
3. You will need to take more care in choosing the right fish for your system since they are less tolerant of poor conditions.

Cold water aquaponics fish offer many benefits that make them a good choice for many systems despite these disadvantages. However, before you can start raising cold-water fish, you need to choose the suitable species for your climate and set up a system that meets their needs.

The Best Fish Species for Cold Water Aquaponics Systems

1. Salmon

Varieties of Salmon Suitable for Aquaponics:

Salmon are renowned cold water fish belonging to the Salmonidae family, prized for their rich flavor and nutritional value. Common varieties used in aquaponics include Atlantic Salmon (Salmo salar) and coho salmon (Oncorhynchus kisutch). These species are chosen for their ability to thrive in cool water temperatures typical of aquaponics systems.

Temperature and Environmental Considerations:

Salmon prefer water temperatures ranging from 10°C to 14°C (50°F to 57°F), although they can tolerate slightly higher or lower temperatures depending on the specific species and life stage. They require well-oxygenated water and are sensitive to ammonia and nitrite levels, which require careful monitoring and management of water quality in aquaponics setups.

Benefits of Salmon in Aquaponics:

1. Nutrient-Rich Effluent Production: Salmon produces nutrient-rich waste as ammonia and solid waste, which serve as valuable nutrients for plants in aquaponics. This natural fertilizer supports robust plant growth and reduces the need for additional external inputs, enhancing the sustainability of the system.
2. Market Value and Economic Potential: Salmon are highly valued in culinary markets worldwide, commanding premium prices because of their taste and nutritional benefits. Integrating salmon into aquaponics systems not only provides a sustainable source of high-quality protein, but also offers potential economic opportunities through direct sale of fish or value-added products.

Salmon's ability to produce nutrient-rich waste beneficial for plant growth, coupled with their market value and economic potential, makes them a compelling choice for aquaponics practitioners aiming to combine sustainable fish farming with plant cultivation. By optimizing environmental conditions and leveraging these inherent advantages, salmon can contribute significantly to the productivity and profitability of aquaponics systems.

2. Trout

Overview of Trout Species Commonly Used:

Trout are a diverse group of freshwater fish belonging to the Salmonidae family, known for their adaptability to various aquatic environments. Common species used in aquaponics include rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta). These fish are valued not only for their culinary appeal but also for their ability to thrive in well-oxygenated, cold water conditions typical of aquaponics systems.

Ideal Temperature and Water Quality Parameters:

Trout thrive in cool water temperatures ranging from 10°C to 20°C (50°F to 68°F), making them well-suited for aquaponics setups in temperate climates. Water quality is crucial, with trout preferring pH levels between 6.5 and 8.0 and dissolved oxygen levels above 5 mg/L. They are sensitive to ammonia and nitrite levels and requires efficient biofiltration within the aquaponics system.

Advantages of Trout in Aquaponics:

1. Growth Rate: Trout are known for their relatively fast growth rate compared to other cold water fish species. This trait makes them desirable for aquaponics practitioners seeking a steady harvest of fish.
2. Feed Efficiency: Trout are efficient converters of fish feed into biomass, requiring less feed per unit of growth compared to some warm water species. This efficiency contributes to cost-effectiveness and sustainability in aquaponics operations.
3. Environmental Adaptability: Trout are adaptable to various water conditions and can tolerate fluctuations in temperature and environmental parameters within reasonable limits. This adaptability allows for flexibility in system management and resilience against minor fluctuations in aquaponics environments.

Trout's ability to thrive in colder water temperatures, coupled with their efficient growth and adaptability, positions them as a favorable choice for aquaponics enthusiasts aiming to integrate sustainable fish production with plant cultivation. 

3.Catfish

Requirements for Raising catfish in Aquaponics Systems:

pH Level: between 5- 7
Stocking Density: one pound of fish for every eight gallons of water
Oxygen Requirements: at least 5mg/L of higher dissolved oxygen concentration.
Water Temperature: between 65-75°F
Tank Size: the ideal fish tank for catfish is a large tank with a diameter of at least 4ft. 
Nutritional Requirements: require high-protein foods like worms or catfish food
Best catfish Breed for Aquaponics: Channel Catfish, eel tailed catfish, brown bullhead

Catfish are a good option for cold-water aquaponics systems. They are tolerant of cold water and can thrive in various habitats, making them a good choice for many types of systems. When raising catfish in an aquaponics system, it is essential to provide them with a habitat that meets their needs and feeds them the right food.

4. Perch

Key Considerations for Choosing Cold-Water Fish

Choosing the right cold-water fish species is critical for the success of aquaponics systems. Here are key considerations to keep in mind:

1. Temperature Requirements:

Ensure the fish species can thrive within the temperature range of your aquaponics system. Cold-water fish typically prefer temperatures lower than those favored by warm-water species.

2. Water Quality Preferences:

Understand the water quality parameters preferred by the fish, including pH levels, dissolved oxygen, and tolerance to ammonia and nitrite levels. Maintain optimal water conditions for the health and growth of the fish.

3. Feed Efficiency and Growth Rate:

Evaluate the fish species' feed conversion ratio and growth rate. Choose species that efficiently convert feed into biomass, balancing growth with the nutrient requirements of plants in the aquaponics system.

4. Environmental Adaptability:

Select fish species known for their adaptability to varying environmental conditions, including fluctuations in temperature and water quality. This resilience helps maintain system stability and reduces the risk of stress-related health issues.

5. Market Demand and Economic Viability:

Consider the market demand and economic potential of the fish species. Some species, like salmon, command higher market prices, which can influence the economic feasibility of aquaponics operations.

6. Compatibility with Plants:

Ensure compatibility between the fish species and the types of plants you intend to grow. The fish should produce nutrient-rich waste that supports plant growth without causing nutrient imbalances or toxicity.

7. Sustainability and Ecosystem Balance:

Prioritize species that contribute to the overall sustainability and ecological balance of the aquaponics system. Avoid species that may disrupt the ecosystem or require excessive management interventions.

8. Practical Considerations:

Factor in practical aspects, such as space requirements, maintenance needs, and regulatory considerations (if applicable). Choose species that align with your available resources and operational capabilities.

Conclusion

Cold-water fish species like trout, salmon, perch, and goldfish demonstrate diverse traits that cater to different environmental conditions and system requirements. Their ability to thrive in cooler temperatures, coupled with efficient nutrient conversion and resilience to varying conditions, underscores their suitability for diverse aquaponics setups across different climates and scales.

As aquaponics continues to evolve and expand as a sustainable farming method, ongoing research and experimentation with different fish species will further refine best practices and enhance system efficiency. By leveraging the strengths of various cold-water fish species, you can continue to innovate and contribute to sustainable agriculture. To learn more about the different fish species for aquaponics systems, read our blog, “The Best Fish for Aquaponics.”