The Best Fish for Aquaponics - Go Green Aquaponics

The Best Fish for Aquaponics

One of the most important decisions you will have to make if you want to start your own aquaponics system is which fish species to use. In an aquaponics system, fish plays a critical role as it produces the natural fertilizers needed by the plants to thrive.

Aquaponics allows you to raise a wide variety of fish species, and there are many options to suit your needs. However, to be successful, you need to carefully choose the best fish species that will survive and thrive in your system. In this article, we will look at the best fish to raise in aquaponics systems.

 

catfish in aquaponics

What To Consider When Choosing Your Fish

To build a successful aquaponics system, you'll need to carefully select the fish that will thrive in your climate, location, and availability. Fish and plants thrive at different temperatures and pH levels, so it is essential to plan what kind of vegetables you want to grow with your fish. It is also necessary to know and plan out the purpose of the fish in your system. Are the fish you are raising for home use, commercial use, or recreational use? Here are some key things to consider in selecting the best fish for your aquaponics system.

Edible vs. Ornamental Fish

Fish edibility will play a significant consideration in your fish species selection. If you're planning to eat your fish, build your system around edible fish species like Tilapia, Catfish, Carp, Largemouth Bass, etc. You can eat these edible fish species, but often, they are more challenging to maintain and require specific conditions. Inedible fish species like Goldfish and Koi are easier to maintain, more resistant to diseases and parasites, and less expensive. Some ornamental fish species like angelfish, tetras, and danios are great for indoor aquaponics systems. 

Temperature

Fish are cold-blooded, and their ability to adjust to an extensive  range of water temperatures is low. Some fish thrive in cold water, while some thrive in warm water. So the first thing you should consider is, Is the fish you're planning to grow capable of surviving your location's temperature range? 

Fish thrive at specific temperatures, and a steady temperature within their correct tolerance range keeps the fish healthy and helps them grow faster. Knowing the temperature changes and the temperature preference of the fish you want to raise will help you choose the best fish for your aquaponics system.

Fish Availability in Your Location

The next important thing to consider is the fish availability in your location. Some fish are available only in some areas; an example is the Barramundi. This fish is not easily available in the US, but is readily available in Australia. The ease of acquiring fingerlings also matters in selecting the best fish to raise in your aquaponics system. Tilapia is the most common fish species used in aquaponics because they are hardy and readily available in most parts of the world. 

What Fish is Legal to Raise in Your Location?

Not all fish are legal to be purchased and grown in some locations. So it is essential to check first with your local fish farming laws to ensure that the fish you intend to use in your aquaponics system is legal in your location.

Fish Type and Maintenance Difficulty

Some fish species are hardy and easy to raise, while others are sensitive and costly to grow. If you don't want to spend a lot of time and effort maintaining your system, choose a hardy fish immune to diseases and parasites. Tilapia, goldfish and Koi are hardy fish and great for beginners in aquaponics.  

Size and Space Requirements

Your fish tank's size will determine what type and amount of fish are suitable for your system. Make sure to learn the adult size of the fish you are planning to raise and the size of the tank needed. Some fish require space to thrive, so be aware of the maximum adult size of the fish you plan to raise. For example, a channel catfish can grow up to 40-50 lbs, so they need a large fish tank of 250 plus gallons. 

Filtration Capacity

The filtration capacity of your aquaponics system determines how many fish you can keep in your fish tank. It would help balance between the fish's needs and the plant's capacity and not over-populate or under-populate the fish. An overcrowded fish tank can disrupt the oxygen level in the water. As a general rule of thumb, you should have a 1-inch fish length per gallon of water.

Breeding Habits 

Fish breeding habits are also one factor needed in selecting fish to raise in your aquaponics system. Some fish species don't reproduce in captivity, while other fish species like tilapia reproduce easily and quickly. Sometimes fast reproducing fish species can create problems in poorly built systems and cause fish stocking density problems. You may need to have separate tanks for breeding fish to spawn and keep the young fish alive and healthy. 

Fish Diet

Fish diets are one of the essential things to consider in fish selection for your aquaponics system. Fish requires the correct balance of proteins, fats, carbohydrates, vitamins, fats, and minerals to thrive and give plants the right nutrients needed for their growth. Fish food choice and fish food nutrient availability can affect the maintenance cost of your system. 

Commercial feed pellets are highly recommended for small-scale aquaponics systems, especially at the beginning. You can also feed homemade fish food to your fish, but you must give special attention because sometimes they are not balanced in the essential nutritional components needed by the fish.

 

Aquaponics Water Quality

Water Quality For the Fish

Ammonia

Ammonia and nitrite are toxic to fish. Ammonia and nitrite are considered harmful when the levels are above 1 mg/liter, although any level of these compounds can contribute to fish stress and other fish diseases. 

pH

Fish can tolerate a wide range of pH, but they thrive at levels of 6.5-8.5. A substantial change in pH levels in a short period can cause problems for the fish. So it is essential to keep the pH stable. 

Dissolved Oxygen

Dissolved oxygen (DO) is necessary for growing fish and beneficial bacteria that convert fish waste into nutrients for the plants. It is recommended that the DO levels in aquaponics systems should be maintained at 5ppm or higher. If the DO levels in your system are too low, increase aeration by using a larger pump or adding air stones. Also, do not overstock the fish in your system to avoid low levels of DO.

Light and Darkness

Reduce the light level in the fish tank to prevent algae growth, but it should not be completely dark, as fish will experience stress and fear when a completely dark fish tank is exposed to a sudden light when uncovered. The ideal light is with indirect natural light through shading, which will prevent algae growth and fish stress.

Fish Selection for Aquaponics System

Edible Fish

Tilapia

Tilapia in Aquaponics

Ideal pH Range: 6.5 - 9. 
Ideal Temperature Range: 82 - 86 °F
Ideal Fish Tank Size: A fully grown tilapia will weigh 1 pound, although they can grow larger. The rule of thumb is that one pound of tilapia will need 3 gallons of water. So this means that in every 3 to 5 gallons of water, only raise one tilapia. 
Food Requirements:Tilapia are omnivores' fish species, which eat both plant and animal-based feed. In aquaponics, you can also feed with leftover vegetables and other alternative or homemade fish food. 

Tilapia is one of the best fish to raise in aquaponics because they are hardy fish and can adapt to their environment and withstand less than ideal water conditions. They are resistant to many pathogens, parasites and in handling stress. 

The harvest time for Tilapia is between six and eight months, depending on how warm the water is, how much they are fed, and the size of fish you want to harvest. Tilapias are easy to breed in small-scale and medium-scale aquaponic systems. Read our in-depth article on how to raise tilapia in aquaponics systems. If you’re looking to purchase tilapia fingerlings, clickhere. 

 

    We Offer Two Types of Tilapia For Sale

    Tilapia For Aquaponics

    Advantages of raising tilapia in aquaponics:

    • Tilapia has a faster growth rate (about nine months from fingerling to harvest).
    • Tilapia is a hardy fish and can quickly adapt to its environment.
    • They are edible and taste great. 
    • Ability to reproduce quickly.
    • They have an omnivorous diet, meaning you can feed with alternative fish food.
    • They are top feeders. You can assess their consumption quickly and adjust accordingly. 

    Disadvantages of tilapia:

    • They require warmer water above 55 °F.
    • Their ability to reproduce quickly can be an issue if you have a small aquaponics system, but there are ways to counteract this. 
    • You always need to keep your water warm in a colder climate.

    Trout

    Trout in Aquaponics Pond
    Ideal pH Range: 6.5-8
    Ideal Temperature Range:14-16°C (57-60°F)
    Growth Rate: 1000 grams in 14 to 16 months
    Average Adult Size:12 kg (27 lbs)
    Food Requirements: Trout requires a higher protein diet than Tilapia and carp. 
    Trout are carnivorous cold-water fish that belong to the salmon family. Trouts are slow-growing fish and can reach about one pound in 4 years in the wild. They are perfect fish for indoor and outdoor systems because they have an excellent temperature range.

    Trout are ideal for aquaponics in Nordic or temperate regions, especially in winter. They have a very high tolerance to salinity and can survive in freshwater, brackish water, and other marine environments. 

    Advantages of trout:

    • Trout tastes good and is loaded with protein and omega fatty acid.
    • Trouts are ideal in colder climates.
    • They feed on various diets, including fish, insects, and soft-bodied invertebrates.

    Disadvantages of trout:

    • Slow growth rate.
    • They can't be kept with other fish.
    • They need plenty of space to ensure their proper growth.
    • Require clean filtered water to live.
    • Fewer plant choices due to their cooler water requirement.
    • Close monitoring of their pH level is essential.
    • Need high dissolved oxygen levels in the water (minimum 10 mg/liter).

    Catfish

      Catfish in Aquaponics
      Ideal pH Range: 7 -8
      Ideal Temperature Range: 65°F to 90°F
      Ideal Fish Tank Size:large fish tank (at least 8 gallons of water per catfish)
      Food Requirements: Catfish requires high-protein foods. They eat pellets, worms, or other homemade fish food. 
      Catfish are a highly hardy group of fish tolerating wide swings in DO, temperature, and pH. They are also resistant to many diseases and parasites. Catfish are the easiest fish to raise for beginners in aquaponics who want to grow fish in locations where the electrical supply is unreliable. Because of their high tolerance to low DO levels and high ammonia levels, catfish can be stocked at a higher density, provided that there is enough mechanical filtration.
      Catfish are the easiest species for beginners or aquaponics growers who want to grow fish with an unreliable electrical supply. Given the high tolerance to low DO levels and ammonia levels, catfish can be stocked at higher densities and provided adequate mechanical filtration.
      Catfish are benthic fish, meaning they are bottom feeders and valuable scavengers that are not territorial and easy to breed and raise. They grow relatively fast and can be harvested within three months. When raising catfish, it is recommended to use a tank with more significant horizontal space than vertical space to allow the fish to spread out at the bottom. You can also raise other fish like tilapia, perch, or bluegill sunfish with catfish in the tank.

      Advantages of catfish:

      • Non-territorial (can be raised with other equal-sized fish).
      • They can tolerate different water temperatures.
      • Good tasting fish for eating.
      • Feed on various plants, bugs, small fish, and pellets.
      • Easy to raise and breed. 

      Disadvantages of catfish:

      • They require high protein food.
      • Catfish do not have scales and are easily stressed or injured when not handled properly. 

      Largemouth Bass

       

        Largemouth Bass
        Ideal pH Range:6-8
        Ideal Temperature Range:65°F - 80 °F
        Ideal Fish Tank Size:A 100 to 150 gal (380 to 570 L) tank is a great size to start with. This would be enough to house eight fish, given they’re no more than 10 inches in length.
        Food Requirements:They are happy when fed with insects and worms, but will also be satisfied with floating commercial pellets.
        Largemouth bass can tolerate a wide range of temperatures, low DO, and pH. However, largemouth bass prefers clean water. They are carnivorous fish, and they require a high protein diet. The growth rates of largemouth bass are dependent on the temperature and feed quality.
        Most of the growth is obtained during the warmer season in temperate climates. Because of their high DO tolerance and resistance to elevated nitrite levels, largemouth bass is one of the best fish to raise for aquaponics farmers, particularly those who cannot change fish species between cold and warm seasons.

        Advantages of largemouth bass:

        • Bass are top feeders.
        • Bass eat almost anything like insects, worms, and pellets.
        • They don't need much protein, giving you more food choices when feeding them.
        • Great-tasting fish to eat.

        Disadvantages of largemouth bass:

        • The potassium levels of Bass need to be monitored as changes in this can make them ill.
        • Their conditions must be monitored closely to ensure clean water, proper oxygen, and pH levels.
        • Bass do not tolerate bright light and have poor feeding habits.

        Salmon

          Salmon Fish in Aquarium
          Ideal pH Range: 7 - 8
          Ideal Temperature Range: 55°F - 65°F
          Ideal Fish Tank Size:A 1000-L tank (264 G) is enough to house four fish for Atlantic salmon. 
          Food Requirements: Salmon can be fed with pellets that contain 70% vegetable ingredients and 30% marine ingredients like fish oil and fish meal. 
          Salmon are great-tasting and one of the best fish to raise in your aquaponics system if you live in a colder climate. They require a larger fish tank to thrive and can take about two years to reach full size.

          Advantages of salmon:

          • Salmon are social fish, tolerant and friendly with other fish.
          • Salmon has a high tolerance for cold conditions.
          • Delicious and healthy to eat. 

          Disadvantages of salmon:

          • They require more food than other fish.
          • Salmon are more likely to contact diseases than many other fish species.

              Ornamental Fish

              Koi

              Koi Fish for Aquaponics
              Ideal pH Range: 6.5 - 8
              Ideal Temperature Range:65°F - 78 °F 
              Ideal Fish Tank Size: A 1000-gallon tank will be enough to have 6-5 koi. They are also ideally grown on ponds. 
              Food Requirements:Koi are omnivores and are not difficult to feed as they will eat plant and animal matter. But for their optimum growth, giving high-quality feed is recommended. You can feed with flakes and pellets that provide a well-balanced diet. They can also eat green vegetables or enjoy worms occasionally. 

              Koi is one of the most popular ornamental fish used in aquaponics. Koi has a long lifespan and can breed and live comfortably within the aquaponic system. Koi can survive off many types of food and are also disease and parasite-resistant. 

              Advantages of koi:

              • Disease and parasite resistance.
              • It can survive in a wide range of temperatures.
              • Ornamental and attractive fish.
              • Long lifespan.

              Disadvantages of koi:

              • Not a good fish for eating.
              • Needs a larger fish tank. 
              • It can produce excess waste as they age and require more cleaning to keep your system healthy.

              Goldfish

                  Goldfish in Aquaponics
                  Ideal pH Range:6 - 8
                  Ideal Temperature Range: 78°F- 82 °F 
                  Ideal Fish Tank Size:At least a 120-gallon tank for five single-tailed goldfish.
                  Food Requirements:Goldfish are omnivorous, meaning you can provide them with a wider range of diet options. However, it is recommended to stick to prepackaged fish feed, preferably high-protein pellets. 
                  Goldfishis an excellent ornamental fish for aquaponics that is easy to take care of. They are hardy fish species that can live in a high level of water pollution. Goldfish prefer temperatures of 78 - 82 °F and prefer a pH range between 6 - 8. Because of their small size and parasitic nature, goldfish are not edible.
                  Advantages of goldfish:
                  • Beautiful ornamental fish.
                  • Hardy fish and tolerant of pH changes.
                  • It can live in polluted water.
                  • Produce lots of beneficial waste nutrients for the plants.
                  Disadvantages of goldfish:
                  • You can't mix them with other fish in one tank.
                  • Not edible.

                    Acclimating the Fish

                    Acclimating fish into the new fish tank can be stressful for the fish, mainly if they just came from the transport of one location to another in small bags or tanks. To acclimatize the fish, keep the new fish in a small aerated tank with their original water for several days and slowly add water from the new one over the day. The two main factors that cause fish stress when acclimating are changes in temperature and pH. 

                    Fish Care

                    Fish highly depend on the water in which they live, so changes in the water will directly affect their health and well-being. Here are symptoms to look for when checking the health of the fish.

                    Symptoms of diseases to look out for:

                    • Cloudy or swollen eyes.
                    • Rapid movement of the gills.
                    • Distended or hollow stomach.
                    • Opaque, clamped, or frayed fins.
                    • Wounds, fungus growth, patches or spots of cloudy white/grey, or color changes in the skin. 
                    • Unusual behavior. (unusual swimming patterns, darting around the tank in an alarmed fashion, hanging at the surface or hiding away and being unusually shy)

                    Causes of Fish Disease 

                    Fish diseases can be introduced by new fish, plants, live food, invertebrates, or equipment used in the system. There should be a delicate balance in the fish tank to ensure that the fish remain healthy. Fish carry bacteria, viruses, fungus, and parasites like all animals. Not all of these are harmful, but some of these microorganisms, called pathogens, can cause diseases. 

                    The following factors can cause fish disease.

                    • Environment or low water quality.
                    • Not getting along with other fish in the fish tank.
                    • Poor or unbalanced diet.
                    • Fish Stress.

                    How to Prevent Fish Diseases

                    • Purchase healthy fish seeds from a reputable and reliable hatchery.
                    • Never add unhealthy fish to the system. Examine and quarantine new fish in a separate fish tank for two weeks before introducing them into an established fish tank. 
                    • Feed the fish with a good, varied, and well-balanced diet.
                    • Keep the water quality in your system clean, including cleaning the filter if you have one fitted to your system.
                    • Ensure the system is within the parameters of pH, ammonia, nitrites, and nitrates for your particular fish.
                    • Add extra aeration. You can rarely have too much aeration.
                    • Reduce the frequency of opening and closing the lid on the tank and minimize scooping fish out to inspect them. 
                    • Treat the disease as soon as it is identified.

                    Conclusion: 

                    The fish species mentioned above are the best fish for aquaponics systems. However, for a successful aquaponics system, choose the right fish that is suited to your location and climate. It is also necessary to prevent diseases from affecting your fish and plants. Feed your fish the right food, not just for their health but also for yours, if you plan to harvest and eat them. Thank you for reading our article. We'd love to hear your feedback in the comments section below. 

                    3 Responses

                    Jazmine Montoya

                    Jazmine Montoya

                    February 08, 2022

                    What kind of High protein food would I give my catfish ?

                    Lori

                    Lori

                    August 05, 2020

                    Wondering about light/dark … for example, if I went with bass in a large tank set into the ground… do the fish want or require an amount of daylight or can they thrive in mostly dark? (very much still in design phase)

                    Thanks for any insight on this as I’m not seeing it mentioned anywhere.

                    Xmegatron

                    Xmegatron

                    March 04, 2020

                    As for me I like the male [SMALLMOUTH BASS] as pets only and I would get a long long long long long wide 40 gallon tank with a tall thick brush of bluepurple tricolor plants I will add 3 pumpkinseed sunfish, 3 semi-aggressive geophagus cichlids and 1 single big male Rio grande texas cichlid.

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