It’s fair to say fish make up half of aquaponics. Fish waste feeds the plants and the plants replenish the water making it clean for the fish. The cycle continues and both plants and fish are harvestable within a few weeks or months.
So it goes without saying, selecting the right fish for an aquaponics system is arguably one of the most important questions to answer.
The amazing thing about aquaponics is it is completely customizable. There are numerous fish to choose from and, with enough research, will fit your systems needs nearly perfectly.
If your system is in a warmer climate – there’s a fish for that. If you’re just starting out and don’t intend eating any of the fish – there’s a fish for that as well.
Nature has created limitless species to fit all manner of niches across the world. Chances are one of these fish listed below will be the right fit for your system.
The Four Factors For Choosing Aquaponics Fish
Before choosing just any fish for an aquaponics system a few criteria that need to be met. There are numerous types to select – all of them have advantages and disadvantages. However, the process becomes much easier when looked at through the lens of what your system actually needs. Luckily, picking the fish is similar to picking the plants. Here are the four primary questions to ask yourself:
This helpful list of fish-picking criteria will help narrow down your results into a workable category. At the end of the day there are numerous species and breeds to choose from. However, not all of them are the best choice for your system’s needs.
Legality – Am I Allowed To Raise This Fish?
Some states do not allow for certain fish to be bred as they are invasive if released into the wild. If any fish are traced back to your system a hefty fine might await. This should be the first step in selecting a fish for your system. Check with your state’s regulations and guidelines to determine if your fish is legal or not.
Environment – What Kind Of Space Will The Fish Live In?
Just like with plants, fish require very specific conditions for optimal growth, if not more so. Determining your system’s environment and what fish it can sustain is the starting point to selecting the right fish. Depending on where you live that will often be a deciding factor if a particular species can be used or not.
Determining system limitations will further narrow the kinds of fish that are available to use in your system. Here are some questions to further understand your system’s capabilities.
What is the water temperature range the fish will be living in? What kind of capacity does the system actually have? How many fish can the tanks sustain for optimal and timely growth? And finally, what about filtration? Will your system be able to turn over the amount of water and still cleanse it thoroughly?
Purpose – Will The Fish Be Eaten?
Will the fish be for show or actually eaten? Or will they serve an entirely different function altogether? Some fish, like goldfish and koi, aren’t suitable for eating. This eliminates one more factor for consideration and might make the fish selection process much easier.
Maintenance Difficulty & Operating Costs
If not accounted for on the front end operating costs can begin to mount quickly. Similar to the environment – your wallet can sustain only so much. Certain fish require much more care and attention than others. These questions are helpful to ask yourself when trying to scale for certain fish.
How much will it cost to initially stock your system? How much will it cost to feed? To control the optimum environment?
Depending on the system you have, cheaper and more affordable fish may be the right call before more expensive fish are introduced into your system.
13 Best Fish For Aquaponic Systems
Most Commonly Used Aquaponic Fish
1: Tilapia
A small Mozambique tilapia. One of the two most popular species to be raised in aquaponics. The other – the Nile variety.
Arguably the most popular fish to be raised in aquaponics, tilapia are on the top of the list. Specifically, the Nile and Mozambique species being the front runners.
In addition, tilapia are known to be one of the oldest fishes ever to be farmed. Tilapia love to live in environments ranging from 72° – 86° F but do best in warmer waters. Tilapia can also handle widespread pH ranges between 6.5 – 9. After about 9 months they are ready for harvesting.
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2: Trout
This brown trout thrives in cold water conditions and thrives with a lot of oxygen.
Known as the cool water fish of aquaponics trout can live in a varied climate but prefer temperatures of 56° – 68° F. The most common varieties are brown, rainbow and brook.
The rainbow species are usually used the most in systems.
Oftentimes growers will alternate between tilapia in the warm months and trout in the colder months.
Trout are slower growers and can take up to 16 months to produce fish weighing 1 pound.
Trout gravitate towards very clean water with pH ranges between 6.5 – 8. Careful observance of pH levels is one of the keys to growing this clean water loving fish.
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3: Barramundi
Barramundi are a premium choice in aquaponics with increasingly high demand.
Barramundi is one of the best fish to be raised in aquaponics. While tougher to manage they excel in growth rates, demand, and tastiness.
Contrastingly to trout, barramundi are definitely warm water fish. Similarly however they need premium water conditions and highly dissolved oxygen levels. Barramundi can live in fresh and saltwater systems.
Be sure to separate and protect barramundi as they grow, the larger ones will eat the smaller fingerlings. Keep temperatures between 78° – 83° F.
They gravitate towards pH ranges between 7.2 – 8. It typically takes around 1 year for them to reach 1 – 4 pounds.
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4: Perch
Perch come in a few varieties and can all be adapted to suit an aquaponic system.
Perch come in a few varieties – Silver, Yellow, and Jade. Perch and all of their varieties differ in needs and will have to be cross examined closely to fit the needs of your system.
Similar to tilapia, however, they are great fish for beginners in their adaptability. Perch tend to like warmer waters ranging from 70° – 82° F.
Silver and yellow perch tend to eat smaller fish, bugs, and shrimp while the jade variety can eat vegetables.
Perch can take up to 16 months to harvest, depending on the variety. In addition, they like pH levels of 6.5 – 8.5
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5: Catfish
Catfish is a delicacy and one of the easiest fish to raise.
Catfish are a staple of the aquaponic world. To be specific, channel catfish are the right choice for aquaponics.
This specific species can handle temperature movement and live with other aquaponic fish (tilapia, crappie, and koi). In addition, they are not territorial and can manage within higher stocking densities.
Known around the world as a tasty treat these fish are also known to survive in particularly polluted waters.
Their hardiness and comfortability make them a great choice for first-timers. Catfish prefer temperatures between 75° – 85° F. Keep pH levels between 7 – 8. Catfish grow so quickly they are ready for harvesting within 4 – 5 months.
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6: Bass
Bass have a large variety of species to choose from which can be suited for your systems needs.
Bass stands out as a versatile aquaponics fish. Depending on the variety they can handle varying temperature and pH ranges, live very long, weigh a lot, and vary in feeding needs.
Varieties include: largemouth (bucketmouth), smallmouth, hybrid striped, Australian, and white bass.
In addition, bass are top feeders, depending on how much food stays at the top is a clear indicator how much food they require. If food starts to sink that means too much food has been issued.
Bass prefer temperatures between 65° – 80° F. They also prefer relatively higher pH levels between 6.5 – 8.5. In about a year the bass should be ready to consume at 1 pound.
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7: Carp
Similar to tilapia in hardiness the carp is great for newcomers.
Carp stand out as a great choice for aquaponics because of their ability to survive low as well as high temperatures. Similar to tilapia they are very hardy fish and can sustain large fluctuations.
They have a robust diet and consume most any food. They prefer temperatures ranging between 68° – 77°. pH ranges for carp should be maintained between 7.5 – 8. Carp can be harvested in 12 to 16 months.
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9: Crappie
Crappie are an Australian favorite and fit the climate perfectly.
Crappie are nice sturdy fish that taste similar to bass and are one of the tastiest panfish to eat. The two main types of crappie suited for aquaponics are the black and white varieties.
There is not much difference between the two other than the white species being slightly smaller than the black.
Crappie prefer temperatures between 60° – 75° F. They operate best in pH ranges between 6.5 – 8.2. It typically takes around 2 years before Crappie can be harvested.
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10: Bluegill
Bluegill are rapidly becoming ideal for aquaponic fish.
Bluegill are becoming more popular choices for aquaponics. Similar to tilapia they are known to be hardy fish. They are omnivorous but don’t need to have a lot of protein in their diets.
Bluegill lean towards a narrow temperature range between 70° – 75° F. In addition they prefer a slightly higher pH range between 7 – 9. It takes around 12 months for bluegill to harvest.
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11: Pacu
Pacu are unique in their need for coverage and protection in the aquaponic tanks.
Don’t get confused – pacu are not piranha’s! They are actually called vegetarian piranhas. Although strikingly similar and originating from similar places they are quite distinct.
Pacu prefer tight temperature ranges between 75° – 80° F. pH ranges for pacu are typically between 6.5 – 7.5.
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12: Salmon
Salmon are one of the toughest fish to raise but one of the healthiest.
Similar to trout, salmon are one of the more difficult fish to raise in aquaponics but pay off in taste and healthiness.
They require very consistent fresh cold water in addition to needing plenty of space. They need water temperatures between 55° – 65° F.
Salmon also require narrow pH ranges between 7 – 8. Depending on the time frame and variety it can take up to two years before salmon begin to reach consumable sizes.
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Non-Edible Fish for Aquaponics
13: Gold Fish
Goldfish are a dime a dozen and can be found everywhere in the world.
Goldfish are similar to koi when it comes to aquaponics. They stand out as hardy fish that are not eaten but serve the same function as all the other fish.
In addition, they look beautiful. Two types of goldfish stand out and are worth mentioning.
The twin-tailed goldfish should not be integrated with single-tailed goldfish as they might die and suffer comparatively to their single-tail counterparts.
Both species however like temperature ranges between 68° – 75° F. They tend to like pH ranges between 6 – 8.
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14: Koi
Koi are one of the most beautiful fish you can raise in aquaponic systems.
Koi are similar to tilapia in a lot of ways. In fact, they are found in most places tilapia are. The awesome thing about koi is oftentimes they have a very high sale value depending on the design.
In addition they are found at numerous pet stores so they are easy to access and source. In addition they have long life spans, easy diets (plants), and resist parasites.
Koi prefer temperatures of 65° – 75° F. They can surprisingly be eaten but I would avoid it. Finally koi love pH ranges between 7 – 8.
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Other Helpful Species In Aquaponics System
Crustaceans
Crustaceans are extremely helpful bottom dwellers and should be seriously considered as viable helpers in the system.
Crustaceans include prawns, crayfish, mussels, oysters, and lobsters. The amazing thing is these bottom dwellers can be included with fish in the system.
They typically take up shop underneath rafts and linger at the bottom. They offer a huge bonus by eating dead organic matter lingering around on the bottom of tanks aiding in cleaning.
Mussels in particular naturally keep tank water clean. They like waters ranging from 57° – 84° F. They have a very short harvest time, about 3 – 6 months. Crustaceans prefer pH ranges from 6.5 – 8.
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Aesthetic Fish For Aquaponics
1: Guppy
Guppies are one of the best options for small and hobby sized systems.
There are numerous varieties of guppies but stand out as a great fish to look at. They are typically used for smaller hobby systems as they cannot be eaten.
Guppies are easy to handle and can be accessed at nearly every animal store around. For very small scale systems they are a great option. They prefer narrow temperature ranges between 74° – 82° F.
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2: Tetra Fish
The tetra fish are one of the most versatile looking fish to purchase for aesthetic and hobbyists.
As with any fish there are many species of tetra fish. They all vary in size and color. Similar to the guppy they aren’t usually eaten and are primarily for looks.
Tetra fish originate from the Amazon jungle and will need to be kept at higher temperatures between 70° – 81° F. They prefer pH ranges between 6 – 7.
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Know Your System!
The easiest way to choose the best fish for your system is by understanding your system. How many fish can your system contain? What temperature range does it operate at? What pH levels does it usually sustain? How much water does it filter in an hour?
There are dozens of fish options each with multiple varieties to choose from. Chances are there are one or two species best suited for where your system is located, its climate, and capacity.
The trick to selecting the right (and best) fish for your system is knowing the limits of what your system can handle and what it cannot.
The more you can understand the limitations of your system the easier it will be to narrow down and select the right fish.
If you live in Australia (with very hot weather) it will be very difficult to raise salmon or trout. Play to your strengths.
The more you try and go outside of what your system can handle the more expensive it will be to operate and maintain.
Written By
Amber Noyes
Amber Noyes was born and raised in a suburban California town, San Mateo. She holds a master’s degree in horticulture from the University of California as well as a BS in Biology from the University of San Francisco. With experience working on an organic farm, water conservation research, farmers’ markets, and plant nursery, she understands what makes plants thrive and how we can better understand the connection between microclimate and plant health. When she’s not on the land, Amber loves informing people of new ideas/things related to gardening, especially organic gardening, houseplants, and growing plants in a small space.