Aquaponics Fish Systems

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Easiest Species To Grow The 5 Best Aquaponics Fish

5 best fish for aquaponics
Image Credit: How to Build an Aquaponic System - Chop & Flip IBC Build, Rob Bob's Aquaponics & Backyard Farm.

When it comes to choosing a species of fish for your aquaponics system, you’ll quickly find that the options aren’t as system dependent as when selecting plants. This is because the fish tank remains the same using any technique, whereas the grow bed varies from method to method, and these differences are more suited to certain species. You will find however, a number of species people consider the best aquaponics fish, so whilst you don’t necessarily need to consider what aquaponics method you’re using when selecting fish, it’s a good idea to choose a species known to thrive in aquaponics, and then make sure you’re selecting a species that’s comfortable in your locate climate, and with the choice of the plants you’ve selected.

In cases where this information isn’t already written in black and white, you will still be able to find all the parameters safe operating ranges for the species of plants and fish you’re interested in. You’ll then need to compare these levels manually to figure out if your fish and plants are compatible to be raised within the same environment.


The 5 Best Fish For Aquaponics Systems

Best Edible Fish For Aquaponics


Without a doubt currently the most popular aquaponics fish used in setups all over the world, tilapia are a hardy species that are ideal for aquaponics thanks to their hardiness, ease of raising, and extremely tasty meat. Tilapia have a number of great advantage over other species, and aside from preferring warmer climates, really don’t have any disadvantages, at least not for those properly prepared.


  • Rapid growth rate
  • High reproduction rate
  • Tolerance to temperature fluctuations
  • Hardiness
  • Delicious mild taste


  • Temperature: Don’t thrive as well in colder climates
  • High Reproduction Rate: Although this can be an advantage, if not properly maintained can quickly lead to over population.

Essential Parameters to Monitor for Tilapia Aquaponics

  • Water Temperature: Min. 75°F / 23.8°C, Suggested 82-86°F / 27.82-30°C
  • pH: 6.5–9.0
  • Dissolved Oxygen (DO): 1–3PPM
  • Tank Size: 1LBS of Tilapia: 3Gallons of Water / 11

5 best fish for aquaponics tilapia

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Whilst not as popular to eat as salmon, trout are in the same family of fish and therefore posses many of the same great traits, but are also much easier to raise then their tastier cousins.


  • Tolerant to cold climates
  • Tolerant to disease
  • High quality meat despite being lesser known


  • Slow growth rate
  • Sensitive to temp fluctuations
  • Large tank size
  • High DO requirements

Essential Parameters to Monitor for Trout Aquaponics

  • Water Temperature: 50-70°F / 10-21°C
  • pH: 7.0-8.0
  • Dissolved Oxygen (DO): Suggested 6PPM. Min.-Max 3–8PPM
  • Tank Size: 1LBS Trout : 10Gallons of Water / 37.8L

5 best fish for aquaponics trout


Salmon are one of the most, if not the most, delicious fish in the world. Popular in many dishes, in high demand and with high market value, their size and temp requirements may make them slightly harder to raise than tilapia, however, there are still a number of benefits you’ll get from choosing salmon for your aquaponics.


  • Tolerant to other fish species
  • Tolerant to cold temperatures
  • Delicious
  • High Market Value


  • Slow growth rate
  • High feeding requirements
  • High DO requirements
  • Large tank size
  • Prone to disease

Essential Parameters to Monitor for Salmon Aquaponics

  • Water Temperature: Suggested 55-65°F / 12-19°C
  • pH: 7.0-8.0
  • Dissolved Oxygen (DO): 6-11PPM
  • Tank Size: 1LBS Salmon : 7-10Gallons of Water / 26.5-37.8L

5 best fish for aquaponics salmon

Best Inedible Fish For Aquaponics


Whilst it’s possible to eat certain species of goldfish, it’s common for most people to leave them off their list of favorite edible fish. So we’ll do the same here. Goldfish make for an ideal choice in aquaponics since they’re hardy and tolerant to fluctuations of any parameter, and they’re extremely affordable, so much so many use them sacrificial fish for testing purposes.


  • Hardy
  • Easy to raise
  • Tolerant to polluted water
  • Affordable
  • Pretty
  • Small tank size


  • Not suitable with other fish as a partner species
  • Inedible

Essential Parameters to Monitor for Goldfish Aquaponics

  • Water Temperature: 78- 82°F / 25.5-27.7°C
  • pH: 6.0-8/0
  • Dissolved Oxygen (DO): 5PPM
  • Tank Size: 1LBS of Goldfish: 4Gallons of Water / 15.1L

5 best fish for aquaponics goldfish

Koi Carp

The beauty of the fresh water ponds, especially in Japan, China, and throughout Asia, Koi is a great choice if you’ve rigged up an aquarium that calls for the best aesthetics. Another large fish that typically requires bigger tanks, but they’re also extremely attractive and relatively easy to raise in aquaponics environments


  • Stunningly attractive
  • Long lifespan
  • Resistant to disease and parasites


  • Large space requirements
  • Large tank size
  • Inedible

Essential Parameters to Monitor for Koi Aquaponics

  • Water Temperature: 65-78°F / 18.3-25.5°C
  • pH: 6.5-8.0
  • Dissolved Oxygen (DO): 6PPM
  • Tank Size: 1LBS of Fish: 5-7Gallons of Water / 18.9-26.5L

5 best fish for aquaponics koi

Key Considerations For Aquaponics Fish

Warm Vs. Cold Water Species
Fish are generally categorized into warm or cold-water varieties. Warm water fish thrive in water temperatures between 75 to 85°F (24 to 29°C), and cold water fish prefer temperatures between 50 to 70°F (10 to 21°C).

It’s highly advisable to let the climate of location to determine what type of use. But remember to take into account the placement of your system. Those building outdoor setups should consider the range of temperature swing between day and night, as well as how much direct sunlight the system is exposed to. Those setting up indoor will need to consider if the area is heated or cooled, and again, what the temperature between day and night, or heating/air conditioning on and off.

Of course, if you’re experienced and have the ability to set up temperature controlled fish tanks then by all means go with either warm or cold-water options.

In much the same way as the location affects the water temperature, it will also affect the amount of the light reaching the system. Too much is bad for several reasons, it promotes the growth of algae that suffocate the system, it can trigger plants to fruit/flower too soon, and it can also cause fish to become stressed, and more susceptible to disease.

Take note of where is best to set up according to the natural light. As a general rule you’ll want to ensure the system receives at least 6-8 hours of light per day, and limit additional exposure to light to prevent the growth of algae.

Growth Rate
This is one of the key factors when aiming to achieve maximum efficiency as the quicker the fish grow and can be harvested, the quicker you can enjoy the benefits of harvest.

Harvesting fish is done in one of several ways; either by netting, trapping, or spearfishing. Each species will have a preferred harvesting method, and you’ll need to take this into account when designing the configuration of the fish tank so the fish can be easily accessed using the correct harvesting method.

Dietary Type
Carnivores, Herbivores or Omnivores? As you may note from the list, it’s possible to use all types of fish for aquaponics. Carnivores tend to consume more, and will produce more ammonia-rich, nitrogenous waste, but in general each type can be just as effective as the next, it largely depends how well you’re able to balance other parts of the system.

No matter the type, be sure to feed the correct amount, not too little and not too much. Under feeding will cause too little waste to be produced for the nitrification process. Whereas overfeeding can lead to excess waste, which is toxic to both plants and fish.


Size and Space Requirements
It goes without saying that different types of fish grow to varying sizes. You’ll need to ensure the fish tank is large enough to accommodate the number of fully-grown adult fish, and you’ll want to keep the size of the fish tank in proportion with the grow bed. If the grow bed is too large and holds too many plants for the size of the tank and number of fish, the waste may not be adequately diluted and sufficient nutrients will not reach the plant’s roots. Overcrowding of either plants or fish is detrimental to the ecosystem, so it’s important not to raise too many fish, or grow too many plants.

Stocking Density
The fish act as a type of control that when adjusted, will in turn alter other levels along the cycle. This is because the fish produce the ammonia-rich waste that the beneficial bacteria used to convert into nitrites for the plants, therefore the amount of waste being produced, together with the size of the beneficial bacteria colonies, both work to regulate the amount of nitrites being produced.

Stocking density of each fish species will vary, however you can follow a general rule of thumb to give the system the best chances of flourishing.

The generally advise ratio for a balanced stocking density in aquaponics is 1:2 / Fish:Plant.

Nitrifying Bacteria and the Nitrification Process
With sufficient numbers of nitrifying bacteria, and the right amount of fish producing waste, the resulting amount of nitrites for the plants will be ideal. However, if there are too many fish producing too much waste, or conversely, too few fish not creating enough waste, then there’s a risk of the nitrification process producing too much, or too few, nitrites for the plants respectively.

As noted, the nitrifying bacteria will play a key part in this role. Similarly, when the colonies of these beneficial bacteria are not large enough then nitrification will be poor, however, in nearly all circumstances you can never really have too much nitrifying bacteria in your aquaponics system, so of course, the most common problem is not having enough of the beneficial bacteria.

So, yet another factor you’ll need to perfect but one that won’t require continual monitoring. Instead this must be achieved prior to plants being grown. Then once sufficient numbers have been reached it’s unlikely they’ll fall too low again, unless of course there are problems, which will be signaled by one of the afore mentioned parameters.

The Importance of Cycling Aquaponics Systems Prior To Growing
This is why every aquaponics growers stresses the importance of cycling the system adequately prior to growing any plants, as without it the system will likely never even being, or at least will not survive.

Cycling refers to starting the nitrification process and allowing it to ‘cycle’ until the bacteria colonies reach sufficient numbers to convert enough ammonia into nitrites. This typically takes from 4-6 weeks, which can cause impatient, and unknowledgeable growers, to ignore the warnings and transplant the plants too quick, not allowing enough time for this process to occur.

Cycling can be done with or without fish, but is fastest without fish since ammonia can be added in greater concentrations than with fish.

If the process seems to be taking too long, you can speed up cycling by introducing additional nitrifying bacteria such as nitrosomonas and/or nitrobacteria.

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Additional Tips and Tricks for Perfecting Your Choice of Aquaponics Fish

Running an aquaponics system is a balancing act, as you adjust one parameter it will change another, and without careful consideration you may find yourself going in circles chasing your tail, constantly causing adjustments further along the cycle and never perfecting the system as a whole.

If you find this is happening, then take a step back and try to approach your solution in a different manner, or if you didn’t begin testing in a logical manner, then start over, and reassess your situation. For example, if nitrite levels are too low, it could be due to insufficient beneficial bacteria, too many plants, or not enough fish, so you’ll need to work through the problem solving using some logic. Decide which parameter it’s likely to be and work through all potential issues before moving on to the next parameter.

Be sure to take notes. These will not only be useful for referencing, you can also use them to logically plan out the order in which you’ll test things; save yourself from getting confused, repeating yourself, or forgetting something altogether.

Most Suitable Plants Compatible For Different Aquaponics Methods

If you’d like to find out what plants are best for each aquaponics technique, then check out our list article below:

Best Plants for Media Based Aquaponics >>> 

Best Plants for Nutrient Film Technique NFT Aquaponics >>> 

Best Plants for Deep Water Culture DWC Floating Raft Aquaponics >>> 

In Conclusion

Selecting fish for your aquaponics system may seem a little daunting, however it’s typically more straightforward then choosing your plants since factors like location and climate will, in part, dictate what species of fish is most suitable for you.

Whether you’re looking for tasty fish to harvest, or inedible fish for that eye-catching aquarium aesthetic, you’ll find a number of options, each of which has its own pro and cons.

From delicious salmon and trout, to the hardy and easy to raise goldfish and tilapia, there’s an ideal species of fish for all aquaponics. And thanks the fish tank not being too different from system to system, it doesn’t matter what aquaponics technique you choose, your choice of fish won’t be affected.

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