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Aquaponics Fish For Most Profitable Harvest

04 Oct, 2023 344
Aquaponics Fish For Most Profitable Harvest - Unimother

How to Choose the Best Fish for Aquaponics

Choosing the right fish for your aquaponics system is a combination of understanding the system's needs, the fish's requirements, and your personal preferences and goals. Research, planning, and a bit of trial and error will lead you to the best choices for your unique situation.

  1. Purpose of Fish:

    • Consumption: Do you intend to eat the fish? If yes, you'll prioritize edible species.
    • Ornamental Fish: If you're more interested in aesthetics, species like goldfish, koi, and guppies might be preferred. They will produce great fertilizer for the hydroponics system. 
    • Commercial: Are you planning to maximize your profit? Shrimps and crayfish are very profitable in many areas while also being beginner friendly.
  2. Personal Preferences:

    • Taste: What kind of fish do you like in terms of flavor and texture?
    • Bones: Consider fish with fewer bones or larger, easily removable bones for easier consumption.
    • Reproduction: Do you want fish that reproduce quickly to replenish stock, or are you looking to keep buying fingerlings?
  3. Plant Considerations:

    • Carnivorous Fish: Their waste is better suited for leafy plants.
    • Herbivorous Fish: Their waste supports fruiting and flowering plants.
    • Omnivorous Fish: Provide a balance suitable for both types of plants.
  4. Diet and Feeding:

    • Consider what you'll be feeding the fish. If you're eco-conscious, you might want to use sustainable feed, kitchen scraps or start your own black soldier fly farm.
  5. Tank Size and System Capacity:

    • Larger fish or higher quantities will require bigger tanks.
    • Determine the maximum number of fish your system can support.
  6. Harvesting Goals:

    • How much fish do you intend to harvest, and how often?
  7. Location and Environmental Factors:

    • Indoor or Outdoor: This will decide your plants and fish options.
    • Water Temperature: Cold or warm water species?
    • Sunlight: Direct sunlight can promote algae growth, which some fish feed on.
  8. Budget:

    • Some fish are more expensive to purchase and maintain. Balance your desires with your budget.
  9. Maintenance and Care:

    • Some fish require more care than others. Determine your commitment level.
  10. Growth Rate: 

    • If you're looking for quicker harvests, prioritize fast-growing species.
  11. Fish to Water Ratio: 

    • Overstocking can lead to health issues and poor water quality. Research the ideal stocking densities for your chosen species.
  12. Availability: 

    • What fish species are readily available in your area? Importing fish can be costly and risky.
  13. Other Considerations: 

    • Nutritional Value: If eating, consider fish high in omega-3s or protein.
  14. Algae as a Filter and Food Source: 

    • Some fish will eat algae, helping to clean the system and getting a natural food source.
  15. Compatibility:

    • Ensure the fish are compatible with each other if stocking multiple species.


Coldwater Aquaponics Fish: Type for Outdoor

In outdoor aquaponics systems, the fish you choose must be compatible with the natural temperature fluctuations of your region, especially if you're in a cold climate. Coldwater fish are great for backyard aquaponics because they can tolerate cooler temperatures, but cold temperatures always mean slower metabolism. So growth time to 1 pound can vary greatly, however I calculated with winter and summer seasons. You should consider starting with big amounts of spawn and over time you can harvest fish and the remaining fish keep growing. 

Here are some coldwater fish suitable for outdoor aquaponics: 

Carnivore = meat based diet

Herbivore = plant based diet

Omnivore = meat and plant diet


Feeding Behaviour

Temperature Range Tolerance

Time to 1 Pound





4°C - 18°C

39 - 64°F

24 - 36 Months

-fatty fish

-best taste

-mid density

need low temperature during summer time

- need very good water conditions

-high water flow and oxygen level

Largemouth bass


4°C - 30°C

39 - 86°F

10 - 18 Months

-always hungry

-Don’t tolerate Constant high temperature

European Catfish


4 - 28°C

39 - 82°F

9 - 12 Months

-great taste

-fast growth

-easy to remove bones

can grow up to 5 meter

Murray Cod


4 - 30°C

39 - 86°F

10 - 16 Months

-Rapid growth rate in first 4 years

-wild numbers are drastically declining 



4 - 30°C

39 - 86°F

9 - 15 Months

-have good resale value

-hardy fish

-become territorial at low stock density

Arctic Char


4 - 15°C

39 - 59°F

15 - 20 Months

-great fish for cold climate

-very healthy and tasty 

-Need constant light first 200 days



4°C - 30°C

39 - 86°F

24 - 36 Months

-mild and sweet taste

-High Density tolerant swarm fish

-not everyone's taste

-many little bones



4 - 35°C

39 - 95°F

24 - 30 Months

-Very social fish

-good taste

-grow slower at bigger sizes

Channel Catfish


4 - 35°C

39 - 95°F

6 - 9 Months

-taste good


-very hard

-easy to reproduce

-sexual maturity after 2 years

Silver Perch


2 - 37°C

35 - 98°F

10 - 15 Months

-High stocking rates

-great harvest

mild taste compared to other fish

Jade Perch


13 - 33°C

39 - 91°F

4 - 6 Months

-Voracious feeders

-very fast growth

-sensitive to high ammonia and nitrate levels

Common Carp


3 - 35°C

37 - 95°F

3 - 6 Months

-tolerant of most water conditions and low oxygen

-can be fed herbivorous

-invasive species if released

-not the best taste

Hybrid Striped Bass


4 - 35°C

39 - 95°F

3 - 6 Months

-can grow up to 22 pounds in the first 2 years

-can not reproduce

White Bass


4 - 33°C

39 - 91°F

12 - 24 Months


-can grow up to 6 pounds



Indoor Aquaponics Fish: Type for Warmwater 

Most of the outdoor fish can also be kept indoors. Only trout are quite picky when it comes to temperature.


Feeding Behaviour


Range Tolerance

Time to 1 Pound



African Mud Catfish


19 -  35°C

66 - 95°F

4 - 6 Months

-eats variety of food scraps

-fast growth

-very tough

-can breath air

-great taste

-easy to remove bones 

-needs high density stock

-low density lead to aggression

-needs constant warm temperature

Tilapia ( Nile, Blue, Mozambique, and many more)


25 - 35°C

78 - 95°F

6 - 8 Months

-very hard fish

-mouth brooders so easy to recreate

-social fish low density fish stock can maintain population

-taste good

-eats almost anything

-big head compared to fish filet



19 - 35°C

66 - 95°F

3 - 4 Months

-extremely fast growth if well fed

-reach 2 lbs in 6 month

- maybe hard to find in your area

Giant Gourami


20 - 35°C

68 - 95°F

3 - 5 Months

-highly intelligent

-ideal pet fish

-eats many food scraps

-behaves like a dog

-taste lovely

-you can’t bring yourself to eat it

-bigger animals can only be kept solo 



20 - 35°C

68 - 95°F

3 - 5 Months

-tender and juicy meat

-great for people who don’t like fish taste

-fast growth

-easy to feed

-low fat content

Snakehead (Channa striata)


22 - 35°C

71 - 95°F

2 - 4 Months

-very low FCR(Food Conversion Ratio) of 0.75

-taste better than catfish

-hard to find fingerlings

Best Edible Fish for Aquaponics

White Flesh Fish:

  • Tilapia: A popular choice for aquaponics due to their hardiness. They have a mild taste and a white, flaky flesh.
  • Pangasius (often known as Basa or Swai): These fish are native to Southeast Asia and have a very mild flavor. They are fast-growing and can reach a size suitable for harvesting in about 6-8 months.
  • Barramundi: Often termed the "Australian Seabass," they have a delicious white flesh. They are suitable for warmer water systems.

Red Flesh Fish:

  • Trout: These fish are suitable for cooler water systems. They have a rich, flavorful red flesh and are packed with Omega-3 fatty acids.
  • Salmon: While typically farmed in large-scale operations, salmon can be considered for larger, more advanced aquaponic systems. They also have a red flesh and are high in Omega-3s.

Bigger Fish (Better for Eating):

  • Catfish (like the African catfish): They can grow in aquaponics quite large and are well-suited. They have a mild nutty flavor and a firm, white flesh.
  • Carp: A traditional fish in many cultures, they can grow quite large. They are hardy and adaptable to various water conditions.

Mild Tasting Fish:

  • Pangasius: As mentioned, they have a very mild flavor, making them suitable for those who aren't fond of a strong fishy taste.
  • Cod: While not as commonly used in aquaponics, cod have a mild, white flesh.

Fatty Fish (High in Omega-3 and Vitamin D):

  • Trout: Particularly rainbow trout, are a good source of Omega-3s.
  • Salmon: One of the best sources of Omega-3 fatty acids.
  • Brown trout: While less common in aquaponics, brown trout is another fatty fish rich in Omega-3s.

African Catfish:

African catfish are versatile eaters and can tolerate a variety of water conditions, making them suitable for aquaponics. Their omnivorous diet allows for varied feeding options, and their potential size means a high yield of meat. In nature they eat fish, insects, birds, mammals, eggs, plant matter like fruits and seeds and grow up to 5 ft 7 in (1.7 m) 130 pounds (60 kg)

Fun fact: big african mud catfish can make loud sounds similar to a crow

When selecting fish for an aquaponics system, it's essential to consider the local climate (as it affects water temperature), available space, and your personal taste preferences. Many of these fish can coexist in a system, but always research compatibility and environmental needs before mixing species.

Tilapia family in an aquaponics pond with algae as extra feed

Easiest Fish For Beginners

Tilapia: A Beginner-Friendly Fish


  1. Hardiness: Tilapia can tolerate a wide range of water conditions including temperature, pH, and water quality. This makes them a hardy fish to raise for common beginners. Mistakes like irregular water conditions from overfeeding or other mistakes tilapia are more forgiving.
  2. Diet Flexibility: Tilapia are omnivorous. This means they can consume a variety of foods, ranging from algae to insects to plants and vegetables, making them less finicky about their diet compared to other species.
  3. Reproduction: Tilapia are mouthbrooders, meaning the female carries the fertilized eggs and young fry in her mouth for protection. This reproductive strategy can make it relatively easy for beginners to breed them in captivity.
  4. Social Behaviour: If there are not too many fish or enough hiding space the baby fish can also survive naturally, survival of the fittest.
  5. Natural Algae Eaters: Tilapia readily consume algae, which can be beneficial in keeping tanks clean while also offering a protein and omega 3 source, especially in outdoor setups where algae growth can be rapid.
  6. Economic Value: Tilapia is a popular fish in many markets and has a mild flavor that is well-received, making them a good choice for those looking to sell fish or use them for personal consumption.


  1. Meat to Bone Ratio: Tilapia have a more prominent head, which can result in a slightly lower filet yield compared to other fish of the same size.
  2. Invasiveness: In some regions, tilapia have become invasive, outcompeting native species. If they escape cultivation systems, they can disrupt local ecosystems. Therefore, it's crucial to ensure they are contained and not introduced to local water bodies.
  3. Disease: While hardy, tilapia can still be susceptible to certain diseases, especially when kept in overcrowded conditions. Regular health checks and maintaining good water quality can mitigate this risk.


Most Profitable Aquaponics Fish


If you don’t like to eat any type of fish, selling is a great way to make some money as a side hustle. The profitability of aquaponics fish varies based on factors like the local market demand, growth rate, food and maintenance costs, and the compatibility with the plants in the system. Prawns and shrimps are often chosen due to their high market value and demand.

Profitability Factors:

  1. Local Market Demand: Before starting, it's vital to research what fish or prawns are in demand in your local market or broader export markets.
  2. Growth Rate: Faster-growing species can lead to quicker returns on investment.
  3. Feed Efficiency: Species that efficiently convert feed into body mass can reduce costs.
  4. Disease Resistance: Species that are less prone to diseases can reduce losses and medicinal costs.
  5. Compatibility with Plants: The fish or prawns you choose should be compatible with the plants in your system in terms of nutrient requirements and waste production.


Prawns and shrimps aquaponics can be very profitable due to their high price per pound or kilogram, especially for certain gourmet varieties. However, as you mentioned, they can be sensitive to water quality and have specific behavioral traits.

  1. Pacific White Shrimp (Litopenaeus vannamei): One of the most widely cultured shrimp species worldwide. They grow quickly and are resilient to various diseases.
  2. Tiger Prawn (Penaeus monodon): Larger than the Pacific White Shrimp, they have a slightly slower growth rate but can fetch a higher market price.
  3. Freshwater Prawn (Macrobrachium rosenbergii): These are suitable for freshwater aquaponics systems and can be grown alongside fish like tilapia.

Crayfish in Aquaponics:

  1. Water Quality: Crayfish are less sensitive to water quality than shrimp, making them somewhat easier to raise for beginners. However, like all aquatic animals, they prefer stable conditions.
  2. Diet: Crayfish are omnivorous and will eat almost anything, including algae, detritus, live plants, and small aquatic animals.
  3. Growth Rate: Most crayfish species will be ready for harvest in 3-6 months, depending on the conditions and species.
  4. Market Demand: Depending on your location, there may be a significant demand for crayfish, especially in regions where they are considered a delicacy.
  5. Self Recreating: Crayfish are easy to multiply and all you have to do is take care and harvest.
  6. Wide Variety of Crayfish: Choose from different species like redclaw crawfish, yabbies, marbled crayfish and many more. You can also check for local species. Beware of releasing any animals into the wild, as crayfish can become invasive very easily and destroy entire ecosystems. Another danger is crayfish plague which is deadly to native species like the European Astacus, but also Japanese and Australian crayfish species seem to be susceptible to this highly infectious water mold disease. 

Compatibility with Other Aquaponics Inhabitants:

  1. Aggression: Crayfish can be very aggressive, especially when they get bigger. They will prey on everything they get their fingers on, especially smaller fish or other invertebrates.
  2. Vulnerable: During molting periods when they're easy to hurt and killed. 
  3. Hiding Spaces: Crayfish need hiding spaces, especially during molting. PVC pipes, pots, or specially designed crayfish shelters can be added to tanks. It needs to have at least two openings else the crawfish gets trapped and eaten.
  4. Plants: They can dig and uproot plants, so if you're integrating them into a system with plants directly in the fish tank (as opposed to separate grow beds), choose sturdy plants or protect the plant roots. They will most likely also nib on your plants. Sharing is Caring.


  1. Market Value: In many places, especially where crayfish boils are popular, crayfish can fetch a good price.
  2. Breeding: Crayfish can reproduce in captivity, allowing for a sustainable and potentially profitable breeding program.

Ethical Considerations:

Like shrimp, crayfish will exhibit natural behaviors, including territorial disputes and the need for hiding during molting. Providing ample space and hiding spots can reduce stress and increase well-being. Crayfish tend to eat each other after shedding their skin, if there is too much of a size difference, not enough hiding space or too dense of a population. An ethically controversial way to solve this problem is to remove the two big claws and all become more peaceful. What is your opinion on this? Removing claws can be similar to practices like declawing cats, defeathering birds or docking dogs' tails, which have been criticized and banned in many regions due to concerns about animal welfare.


  • Reduced Aggression: Without their main weapon, shrimps and crayfish become less aggressive, as they can't induce injuries to each other and reduce stress and deaths in densely populated tanks.
  • Higher Survival Rates: This can lead to happier and healthier populations, yields and profitability.
  • Regrow: Given enough time the claws will regrow after a few moldings.


  • Animal Welfare Concerns: The removal of claws can be painful and stressful for the shrimps for a short moment.
  • Natural Behaviors: Claws are essential for various natural behaviors, including hunting, climbing, mating and defense.

Personal Opinion: It's crucial to prioritize animal welfare in any farming or aquaponics system. While maximizing profitability is essential, it shouldn't come at the expense of the well-being of the animals in the system. If claw removal is being considered, it's vital to ensure the process is as humane as possible and to weigh the pros and cons. Ideally, optimizing tank conditions, providing ample hiding spaces, and maintaining proper stocking densities can reduce the need for such interventions.

Especially adding floor area levels can make use of height and increase the living space for crayfish and shrimps.

Ornamental Fish

Here's a list of popular ornamental fish suitable for aquaponics:

1. Goldfish (Carassius auratus):

  • Description: These are one of the most popular ornamental fish and come in various colors and patterns.
  • Benefits: Hardy, tolerant of various water conditions, and produce a good amount of waste beneficial for plants.

2. Koi (Cyprinus rubrofuscus):

  • Description: Large, colorful fish often found in decorative ponds.
  • Benefits: Hardy, resistant to many diseases, and produce significant waste.

3. Guppies (Poecilia reticulata):

  • Description: Small, colorful fish with a variety of tail shapes.
  • Benefits: Breed rapidly, tolerate various water conditions, and are great for smaller systems.

4. Bettas or Siamese Fighting Fish (Betta splendens):

  • Description: Vibrant fish known for their flowing fins and aggressive nature towards other males.
  • Benefits: Suitable for small systems and can be kept in individual compartments or tanks.

5. Swordtails (Xiphophorus hellerii):

  • Description: Medium-sized fish known for the extended lower part of their tails.
  • Benefits: Hardy, breed easily, and are active swimmers.

6. Platies (Xiphophorus maculatus):

  • Description: Small, brightly colored fish.
  • Benefits: Peaceful, breed readily, and are tolerant of various water conditions.

7. Angelfish (Pterophyllum):

  • Description: Distinctive triangular-shaped fish with long, flowing fins.
  • Benefits: Graceful swimmers, suitable for larger tanks.

8. Tetras (Various species):

  • Description: Small schooling fish, with many species like Neon Tetra, Cardinal Tetra, and Glowlight Tetra.
  • Benefits: Active, colorful, and great for adding movement to the system.

9. Zebrafish (Danio rerio):

  • Description: Small striped fish, often used in scientific research.
  • Benefits: Hardy, active, and breed easily.

10. Mollies (Poecilia spp.):

  • Description: Medium-sized fish that come in various colors and fin shapes.
  • Benefits: Adaptable to various water conditions and breed readily.

Secret tip for money dwellers - dwarf shrimps like crystal red shrimps are traded like kois with high grade S, SS or above can bring over 50$ to 1000$ per shrimp and each is only one inch max. 

Other Livestock and Aquaponics

If you have various animals or space you can also include those into an aquaponics system or adding grow beds to existing systems. For example if you use them in a pond the sunlight will grow algae as extra food while you can simultaneously grow herbs and vegetables, here are a few guidelines to integrate hydroponics and also fish can be added:

  • Turtles:

    • Turtles produce waste that is beneficial for plants.
    • Ensure the water temperature and pH levels are suitable for both turtles and plants.
    • Be cautious about the type of plants you grow in the fish tank, as some turtles will eat or damage them if they are in reach
  • Alligators:

    • Alligators require a lot of space and produce a lot of waste.
    • Their waste can be used in the hydroponics system, especially if you already have a large-scale setup. This will remove any necessary water changes.
    • Safety is a concern. Ensure the alligator area is secure to prevent escapes and to protect handlers.
  • Pigs & Cows:

    • Pigs and cows don't live in water, but their waste can be integrated into an aquaponics system.
    • Consider having a platform where pigs can be above the water, or move their waste drops into the water below.
    • Ensure the waste doesn't overwhelm the system. Regularly monitor water quality and add more grow beds.
  • Ducks:

    • Ducks are great for aquaponics. They help control pests and their waste is beneficial for plants.
    • Duckweed can be grown on the water surface as a food source for ducks.
    • Ensure there's a safe area for ducks to nest and rest.
  • Rabbits & Chickens:

    • Like pigs, they don't live in water. However, their cages can be positioned over water tanks so their waste can be used in the system.
    • Ensure cages are secure and provide a comfortable environment for the animals.
    • Monitor water quality to ensure it doesn't become too polluted.
  • Humans:

    • Human feces can also be used for aquaponics and hydroponics.
    • In vietnam people used to go to the toilet above the water eaten by pangasius below, maybe because of that some people love the taste of the fish. 
    • Fish can still be eaten and grow beds can make use of fertilizer for perfect circular systems.
    • For most people luckily this is something they never have to experience, but in cases of rare resources like in the desert or on mars this could be very useful.

Purpose of Aquaponics Systems when Farming Fish

1. Improved Water Quality:

  • Ammonia Reduction: Fish excrete waste, which includes ammonia. High levels of ammonia are toxic to fish. In an aquaponics system, nitrifying bacteria convert this ammonia to nitrites and then to nitrates, which are less harmful and are used by plants as a nutrient source.
  • Constant Filtration: The plants act as a natural filter, continuously absorbing these nitrates, some are also able to absorb ammonia and nitrite directly, which results in cleaner toxic free water that's recirculated back to the fish tanks.

2. Sustainability:

  • Reduced Overfishing: By cultivating fish in controlled environments, there's less reliance on wild fish stocks, helping to reduce overfishing in natural water bodies.
  • Water Conservation: Aquaponics systems use significantly less water than traditional farming methods because water is recirculated in the system.
  • Reduced Land Use: Aquaponics systems can be stacked vertically, allowing for more efficient use of space and less land requirement.

3. Economic and Environmental Efficiency:

  • Lower Transportation Carbon Footprint: Localized aquaponics systems can provide fresh fish and produce to local communities, reducing the need for long-distance transportation and the associated carbon footprint.
  • Reduced Use of Single-Use Plastics: With local production and direct sale, there's less reliance on plastic packaging that's common in supermarket goods.

4. Health and Safety:

  • Chemical-Free: Aquaponics systems can be run without the use of synthetic pesticides, herbicides, or antibiotics, resulting in organic produce and healthier fish.
  • Reduced Contamination Risk: Closed-loop systems have a lower risk of contamination from external sources.

5. Efficiency and Productivity:

  • Dual Production: Aquaponics allows for the simultaneous production of fish and plants, maximizing yield and profitability.
  • Use of Greywater: Aquaponics can use greywater like vegetable washing water, further promoting water conservation.

6. Convenience and Aesthetics:

  • Home Systems: For hobbyists, having an aquaponics system at home ensures a constant supply of fresh herbs and even fish. It's also an educational tool for understanding ecosystems.
  • Aesthetic Appeal: In addition to their functionality, aquaponics systems, especially ornamental ones with colorful fish and plants, can be visually pleasing and can serve as a focal point in gardens or interiors.


Water Quality for Aquaponic Fish

Maintaining optimal water quality is crucial for the health and well-being of fish in aquaponics systems.

1. Optimal pH Levels for Fish in Aquaponics Systems:

  • General Range: Most fish thrive in a pH range of 6.5 to 8.0.
  • Specific Needs: Different species might have specific pH preferences. For instance, trout prefer slightly alkaline to neutral pH levels, while tilapia can tolerate a broader range.
  • Plants & Bacteria: It's essential to balance pH for both fish and plants. Most plants prefer a slightly acidic pH (5.5 to 7.0). Beneficial bacteria involved in the nitrogen cycle also have pH preferences, typically around neutral.

2. Temperature Requirements for Different Fish Species:

  • Coldwater Fish: Species like trout prefer temperatures between 50°F (10°C) and 65°F (18°C).
  • Warmwater Fish: Species like tilapia thrive in temperatures between 70°F (21°C) and 90°F (32°C).
  • Transition Periods: Gradual changes are essential. Rapid temperature fluctuations can stress fish, so any adjustments should be made slowly.

3. Dissolved Oxygen Levels Needed for Fish Health:

  • General Requirement: Most fish require dissolved oxygen levels above 5 mg/L. Higher levels, around 6-8 mg/L or more, are even better.
  • Factors Affecting Oxygen: Warmer water holds less oxygen than colder water. Additionally, more significant fish biomass and plant density can deplete oxygen faster.
  • Aeration: To ensure adequate oxygen levels, air stones, diffusers, or waterfalls are used to aerate the water.

4. Nitrogen Cycle in Aquaponics and Its Importance:

  • Ammonia Conversion: Fish breath out ammonia through the gills. Ammonia is toxic to fish, even at low levels.
  • Nitrifying Bacteria: Beneficial bacteria convert ammonia to nitrite (also toxic) and then to nitrate (less toxic). This conversion process is vital for fish health.
  • Plant Role: Plants absorb nitrates, nitrite, and some also ammonia aiding in water purification and providing the necessary nutrients for their growth.

5. Monitoring Ammonia and Nitrate Levels in the System:

  • Ammonia: Levels should ideally be close to 0 mg/L. Levels above 1 mg/L can be harmful, depending on the pH and temperature.
  • Nitrite: Like ammonia, nitrite levels should be close to 0 mg/L. Elevated levels can harm fish.
  • Nitrate: Acceptable levels are typically below 150 mg/L, though plants will utilize nitrates as nutrients, helping to keep levels in check.
  • Testing Kits: Regularly test the water using aquarium or aquaponics-specific testing kits. These kits can measure pH, ammonia, nitrite, nitrate, and sometimes dissolved oxygen. Stripes are accurate enough, but if you want to know the exact values only water tests with liquid drops can tell you the truth.

Introducing Fish to Aquaponic Systems

Introducing fish to an aquaponics system requires careful attention to ensure the health and well-being of the fish. Here's a guide based on the points you've mentioned:

1. Understanding the Importance of Acclimation:

While many experienced aquaponics practitioners might have their methods and shortcuts, it's generally a good practice to acclimate new fish to the system. This is especially true if:

  • The fish have undergone long transportation.
  • There were temperature fluctuations during transportation.
  • The fish species are known to be sensitive to changes in their environment.

2. Starting the Fish Cycle in an Aquaponics System:

Incorporating Bacteria:

  • Earthworms or Red Wigglers: Introducing these into the grow bed can jump-start the establishment of beneficial bacteria. These worms bring along bacteria that help convert toxic ammonia into nitrite and then into less harmful nitrate.
  • Plants: If you have a significant number of plants ready to be integrated, you can add fish simultaneously. The plants will help absorb any initial spikes in ammonia and nitrite, protecting the fish. 

Our plant guide gives you ideas for flavors you want in your life.

3. Acclimating New Fish into the System:

Step-by-Step Process:

  1. Floating the Bag: Upon receiving the fish, float the sealed bag on the surface of the tank. This helps equalize the temperature inside the bag with that of the tank.
  2. Turn Bag Top Inside Out: This will allow the bag to float without taking in water.
  3. Gradual Water Introduction: Slowly add small amounts of water from the tank to the bag over a period of 30 minutes to an hour. This gradual introduction helps the fish acclimate to the pH, hardness, and other water parameters of your system.
  4. Transferring the Fish: Using a net (or your hands if you're gentle and it's safe for the species), transfer the fish from the bag to the tank. Make sure not to introduce the transport water into your system, as it might contain chemicals or contaminants.
  5. Observe: Monitor the fish for any signs of stress or discomfort. Make sure they are swimming normally and not showing any distress.

4. Additional Tips:

  • Quarantine: Even if you've never had issues, quarantining new fish can be a good practice. It helps ensure that any potential diseases or parasites aren't introduced into your main system.
  • Transport Water: As you rightly mentioned, it's crucial not to introduce transport water into the system. Some suppliers use tranquilizers or other chemicals to reduce fish stress during transport.

While there are various methods and beliefs regarding introducing fish to aquaponics systems, the primary goal remains the same: ensuring the health and well-being of the fish. Being patient and attentive during this process can lead to a thriving and productive aquaponics system.


Ensuring Fish Health

Ensuring fish health in an aquaponics system is of paramount importance, not only for the welfare of the fish but also for the overall productivity and balance of the system.

1. Prevention of Disease, Stress, and Parasites:

  • Improve Food Quality: Ensure fish are fed a balanced diet appropriate for their species. Quality feed rich in protein and omega 3 promotes better growth and immune response.
  • Sunlight: While direct sunlight can help fish synthesize certain vitamins, be cautious not to overheat the water or cause excessive algae growth.
  • Water Quality: Maintain appropriate pH, ammonia, nitrite, and nitrate levels. Regularly monitor and adjust as necessary.
  • Avoid Overstocking: Overcrowding can lead to stress, oxygen depletion, and rapid spread of diseases.
  • Increase Plant Density: More plants can help absorb excess nutrients, thus improving water quality.
  • Water Changes: If water conditions deteriorate, partial water changes can help reset the balance. However, in a well-balanced aquaponics system, frequent water changes should not be necessary.
  • Increase Tank Size: If feasible, provide a larger swimming area for fish, reducing stress and potential aggression.
  • Avoid Toxins: Ensure that no harmful chemicals or substances come in contact with the system.

2. Causes of Diseases:

  • Dirty Water: Leads to a buildup of harmful substances that can stress fish and lead to diseases.
  • Overcrowding: Too many fish in a limited space can increase aggression, stress, and disease spread.
  • Inadequate Filtration: Without proper filtration, harmful substances can accumulate.
  • Grow Bed: To small grow beds or insufficient pump power can lead to dirt staying in the tank.
  • Overfeeding: Fish can also die from being too fat.
  • Malnourishment: Contrary fish without enough protein and fat can get sick easier.
  • Poor Quality Feed: Can lead to malnutrition and increased susceptibility to diseases.
  • Toxins: Chemicals or other contaminants can introduce diseases or weaken fish.

3. Enhancing Disease Resistance:

  • Gravity Sand Filter: Helps remove suspended particles and potential pathogens.
  • Earthworms: Contribute to breaking down fish waste, reducing harmful substance buildup while also killing pathogens and parasites.
  • Regular Observations: Always monitor the behavior and appearance of your fish. Early detection of any anomalies can lead to quicker interventions and better outcomes.

4. Addressing Weaker Fish:

  • Isolation: If a fish appears sick or stressed, consider isolating it in a separate tank to prevent disease spread and to closely monitor its condition.
  • Veterinary Advice: If multiple fish show signs of disease, it might be beneficial to seek advice from a fish veterinarian or specialist.

dead tilapia with open wounds from fights

Common Fish Diseases In Aquaponics And Their Symptoms

Crowded fish tanks are always hotbeds for parasites and diseases. A grow bed with gravity sand filter and earthworms removes many of those diseases from the water to fish waste.

Also keep in mind that there is always a small number of fish that are lacking behind in size and will fall back further and further as time progresses. They are most deceptive to getting sick.





Infectious Abdominal Dropsy

Swollen belly, popped eyes, protruding scales, permeable feces

Stress, bad fish diet, inappropriate water conditions

Antibiotics, salt baths, and maintaining good water quality

Open Wounds and Ulcers

Visible wounds, ulcers, and lesions on the fish's body

Overpopulation, aggression, bad water conditions, stress

Clean the tank, treat with antiseptics or antibiotics, and improve water conditions


Rotting fins and skin, slow growth, body malformation, mortality

Overpopulation, aggression, bad water conditions, stress

Antibiotics and maintaining good water quality

Anchor Worms

Scratching against objects, whitish-green threads protruding from the fish's skin, inflammation at attachment points

Introduced by infected fish

Physically remove the parasite, clean the wound with antiseptic, seawater bath

Body Flukes

Scratching against objects, mucus layer covering gills or body, rapid gill movement, damaged gills or fins, reddened skin

Poor water quality, overcrowding, stress

Improve water conditions, maybe caused by aggresion

Clamped Fin

Fins folded against the body, listless behavior

Various problems including bad water quality and parasites

Improve water conditions, aquarium salt

Fish Ick

Salt-like spots on the skin, scratching, clamped fins, gasping at the surface

Stress, rapid temperature and pH fluctuations

Improve water conditions, aquarium salt


Gray or whitish growth on skin/fins, cottony appearance

Fish already in a vulnerable state due to other health problems or attacks

Antibiotics and fungicides, improve water conditions

Gill Flukes

Infected gills and skin, rapid gill movement

Poor water quality, overcrowding, stress

Improve water conditions, Praziquantel

Gill Mites

Gasping at the surface, partially open gill covers

Introduced by infected fish

Octozin and sterazin

Hemorrhagic Septicemia

Hemorrhaging of internal organs, skin, muscle, bulging eyes, bloated abdomens, open sores, abnormal behavior

Infection by the Viral hemorrhagic septicemia virus (VHSV or VHSv)

No known cure, treat secondary infections with antibiotics or general cures


Fish rubbing against objects, tiny pale crabs-like dots on fish, inflammation at attachment points

Introduced by infected fish or from wild fish

Quarantine new fish,Physically remove the parasite, clean the wound with antiseptic, seawater bath

Ragged Tail Fin

Progressive deterioration of the tail, frayed or faded fins

Bacterial infection, especially in aquariums with poor conditions

Improve water conditions, aquarium salt, antibiotics

Tail, Fin and Mouth Rot

Progressive deterioration of the tail/fins, frayed or faded fins

Bacterial infection, especially in aquariums with poor conditions

improve water conditions, aquarium salt, antibiotics


Just like humans, fish get sick easier when they are constantly stressed, have a bad diet or are constantly poisoned by polluted water. The treatment is simple: better living conditions. 

Many of these diseases are connected to bacteria and the reason why fish farms have such high antibiotics usage. That doesn’t mean all bacteria are bad. Instead those bacteria infections only break out if water conditions like low oxygen, ammonia, nitrite, too much dirt, temperature, not filtered fish feces, overpopulation or constant stress is prominent. Healthy fish don’t ever get sick even though all the same bacteria are present.

In extreme cases you can separate individuals and treat them in a quarantine tank.

Fish are like any other pet: they need good food and some pats to know they are loved. 


Fish Feed and Nutrition

Providing proper nutrition is essential for the health and productivity of fish in an aquaponics system. Whether you choose commercial feeds, homemade recipes, or a combination of both, ensuring a balanced diet will lead to healthier fish and a more successful aquaponics experience. This will also ensure the fish you eat will have the highest possible quality and rich in omega 3.

1. Protein and Fat Requirements for Fish:

  • Stages of Life: Many fish species start as carnivores in their juvenile stages, requiring higher protein diets. As they mature, their dietary needs may shift.
  • Protein & Fat Sources: High-quality commercial fish feed, insects, mosquito larvae and certain types of water organisms like water fleas or amphipods can be excellent protein sources. These foods are rich in essential omega-3 and omega-6 fatty acids, beneficial for both fish and humans consuming them.

2. Carbohydrate Requirements for Fish:

  • Processed Carbohydrates: Similar to humans, excessive processed carbs like sugar, white flour products like bread, pasta, rice and other carbohydrates can lead to health issues in fish, including obesity and related complications.
  •  Beneficial Carbs: Fiber-rich foods, like certain greens and vegetables, can be beneficial for omnivorous and herbivorous fish, aiding in digestion and promoting gut health.
  • Benefits of Feeding Scraps: Using food scraps can be sustainable and efficient, reducing waste and providing varied nutrition for fish.

3. Micronutrient Needs of Aquaponic Fish:

Micronutrients in fish work similar to how they interact in our body: 

  • Potassium: Vital for nerve function and muscle control.
  • Magnesium: Important for various biochemical reactions in the body.
  • Selenium: An essential trace element that supports the immune system.
  • Zinc: Important for growth, immune function, and wound healing.
  • Iron: Vital for blood health and transporting oxygen.

4. Commercial Fish Feed Options:

  • Pelleted Feed: These are formulated to provide balanced nutrition for fish. They come floating or sinking and in different sizes for various fish stages.
  • Specialized Feed: Depending on the fish species, specialized feeds are available that cater to specific dietary needs.

5. Homemade Fish Feed Recipes:

Creating homemade fish feed allows for more control over the ingredients, ensuring fresh and varied nutrition. Here's a basic recipe:


  • Fresh/dried fish (like sardines or mackerel) or fish meal for protein. You can a
  • Vegetables (like spinach, carrots, and peas) for vitamins and fiber.
  • Grains (like quinoa or oats) in limited amounts.
  • Spirulina powder for added protein, fat and micronutrients.


  1. Blend all ingredients together to create a paste.
  2. Spread the paste thinly on a baking sheet.
  3. Dry in an oven at a low temperature or use a dehydrator.
  4. Once dried, break into small pieces suitable for the size of your fish.
  5. Store in a cool, dry place.

In the same way our body is made from things we consumed in the past, the quality of your food you produce is the direct result of the ingredients you feed the fish during their lives.

Feeding herbs, salads, leafs and vegetables regularly to keep their digestive system healthy like humans need them as well. This way we don't have to compost food scraps but instead feed it and keep the higher energy potential of calories instead of fertilizer. Also we produce less organic waste in our garbage that ultimately ends in landfills where it gets contaminated and becomes unfit for consumption while also  producing methane.

Algae as fish feed rich in protein and omega 3 fatty acids

Feeding Fish for Health

  1. You are what you eat. The quality of the fish fatty acids is only as high as of the food you feed because fish are not able to produce omega 3 themselves. Only plants and algae can produce omega 3. But plant omega 3 is not the same as algae and fish fatty acids: EPA, DHA and ALA differs in content. Plants contain mostly ALA but not EPA and DHA and the human body has limited ability to convert ALA into EPA or DHA. DHA levels are high in the eyes retina, the brain, sperm, and have essential functions in the heart, vascular system, immune system, endocrine system and lungs.
  2. All commercial feed has chemical preservatives because omega 3 is an unsaturated fat that oxidizes really quickly therefore becomes toxic. Until we find more natural preservatives which derive from seeds and nuts that are water soluble this is a fact we must accept. I think the most sustainable way to ensure your fish has sufficient omega 3 is to supplement algal algae or krill oil.
  3. Grow your own algae. Algae is special compared to other plants because they convert nitrogen directly into amino acids and carbon directly into fatty acids, grow very fast, stay productive with 24 hour light on cycle if nutrients and co2 are sufficient while plants reduce their productivity after a certain amount of hours of sunlight.
  4. Feed food scraps like vegetable cut offs or leftovers except meat and sauces, make sure they are in mouth sized pieces for the fish to consume.
  5. Remember lower temperatures require less feed than higher temperatures. Below 10°C or 50°F many fish stop eating or minimal amounts. So do your research on your specific fish. 
  6. Feed more often with small amounts instead of bigger amounts irregularly. This will help smaller fish to get better chances of eating enough food.
  7. Use worms and black soldier fly to convert unsuitable organic waste into protein and fat and to ensure sufficient protein content
  8. Feed excess, old, dry, rotten herbs and leaves to your fish. I have noticed my fish really love welsh onions.
  9. Grow some plants for your fish on the water: Duckweed and azolla are protein rich and contain omega 3. All of these plants filter the water while also offering valuable food. For example, water spinach contains lots of vitamins, minerals and antioxidants, and you can consume all of these yourself as well!
  10. Grow plants for your fish: moringa, Malabar spinach, pechay, sweet potato leaves, parsley, chili leaves and almost any leafy green that is edible can be fed.

Breeding and Reproduction

- Breeding techniques for aquaponic fish

Every fish is different. goldfish start to hunt each other, other fish start separating into one corner and start aggressively defending it, while tilapia mothers will keep the eggs and baby fish in her mouth until they are developed. She lets them out so the babies can eat and when a potential predator comes they swim into her mouth. This makes it very easy to reproduce them, as you can just catch the mother into a separate tank and start feeding the babies. 

- Sex determination in fish 

For many fish it is very hard to determine the gender for a beginner as they don’t have any external differences. But this is not necessary because they will find pairs by themselves if water and living conditions are good.

Usually if female fish are ready to lay eggs she will develop a so-called egg spot. That looks like a stinger and sticks out more and more as she gets closer to egg laying. On mating day the male will also develop a small stinger but thinner than the females.

- Spawning conditions and requirements 

If your system is working well and you have fish that can spawn in freshwater, it is very likely that your fish will spawn sooner or later. The only problem is that most of the time other fish mates eat the eggs or the baby fish instantly if the tank has no hiding structure. When you notice your fish mating just catch them in a separate tank. Try to connect the water of the separate tank and your aquaponics system to keep the filtering power of the whole system. Do some research about your specific fish as no fish is like no other. 

Incubation and Hatching Processes of Fish

  1. Spawning: This is when fish lay their eggs. Some species lay eggs in nests or on the floor, while others release eggs into caves, tubes or on the water column.
  2. Fertilization: For many species, fertilization happens externally. The male releases sperm into the water, which fertilizes the eggs. This process can also be done manually.
  3. Incubation: This is the period between fertilization and hatching. The duration varies between species.
  • Temperature: The temperature of the water can affect the speed of development. Cooler water can slow development, while warmer water can speed it up.
  • Oxygen: Oxygen is essential for the developing embryos. In some setups, air stones or gentle water movement can help ensure adequate oxygen levels.
  • Protection: Depending on the species, parents might guard the eggs, or the eggs might be left alone. In an aquaponics setting, it's necessary to separate the eggs from other fish to prevent them from being eaten.
  • Dried sea ​​almond tree leaves: Can be added for extra natural protection as they reduce bacteria concentrations and fungal infections.
  1. Hatching: When the embryo is fully developed, it will break free from the egg. At this stage, the fish is called a "larva" or "fry."

Care for Fry and Juvenile Fish

  1. Separation: To protect the fry from being eaten by larger fish, you have to separate the eggs and spawns into a different tank or a breeding box within the same tank.
  2. Feeding:

The first few days the new spawns eat from their egg yolk. Feed small amounts often. Yellow from a chicken egg is ideal and everybody has it at home.

  • Infusoria: These are tiny organisms that are ideal for feeding very small fry.
  • Baby brine shrimp: As the fry grow, they can be fed baby brine shrimp.
  • Crushed flakes/pellets: When they're larger, fry can be fed finely crushed fish food.
  • Yellow from the egg: Cook it and crush it with your hands. 
  1. Water Quality:
  • Frequent water changes: I noticed my baby fry are less sensitive to water quality then their adult counterpart. Regular, small water changes can help keep the water clean without causing dramatic shifts in water parameters. You can also set up a small pump that pumps the water into the fry tank and flowing back into the main tank.
  • Gentle filtration: Strong currents can be harmful to fry. Using aeroters creates water flow and the flow can be adjusted to the air flow rate to create a safe environment. An air lifting sponge filter is cheap and can easily be made DIY.
  1. Growth Monitoring: As fry grow, they might need to be separated based on size to ensure that larger fry don't bully or eat the smaller ones. Trust me once you start licking blood with your aquaponics system you will set up more and more tanks because it’s never enough space.
  2. Gradual Introduction: Once the fry have grown sufficiently to not be feed for the bigger fish, they can be introduced into the main aquaponics. This should be done gradually to allow them to acclimate to the new environment and the presence of larger fish.
  3. Health Monitoring: Keep an eye out for signs of disease or stress, such as clamped fins, erratic swimming, or discoloration. Prompt action can prevent the spread of disease and increase the survival rate of the fry. You should always try to improve living conditions instead of adding chemicals.

Remember, the specific care and incubation processes can vary massively based on the species of fish, so it's essential to research the particular needs of the species you're working with. 

Interesting fact: Discus fish fry behave like mammals as they feed on their parents mucus for the first two to three weeks. 


Fish Behavior and Compatibility

Just like cats and dogs, fish are individuals so what works for me may not work for you. Also many factors influence their behavior. 

  • Tank size
  • Population Density
  • Temperature
  • Light
  • Feed Abundance
  • Water Clarity
  • Visual Distance
  • Structure
  • Hiding Space
  • Other Predatory Sized Fish
  • Water Conditions


1. Social Behavior of Different Fish Species

Fish can be categorized based on their social behaviors:

  • Schooling Fish: These fish prefer to stay in groups and feel safer when they're with their own kind. Most small fish start as swarms to protect themselves from bigger predators.
  • Solitary Fish: These fish prefer to stay alone and can sometimes be aggressive towards their own species. Examples include many species of perch.
  • Pairs or Small Groups: Some fish prefer to stay in pairs or small groups. Examples include goldfish and koi.

2. Aggression and Territoriality in Aquaponic Fish

In aquaponic systems, fish are often kept for their waste production to benefit plants. Common aquaponic fish include tilapia, catfish, and carp.

  • Tilapia: While generally peaceful, they can become territorial, especially during breeding.
  • Catfish: They are generally non-aggressive but can be territorial at low stock density.
  • Carp: Depending on the species and environment, carp can range from peaceful to somewhat territorial.

3. Compatibility Between Different Fish Species

When combining species, consider:

  • Size: Larger fish might eat smaller fish. Everything that fits the mouth is seen as food
  • Diet: Ensure that all species have their dietary needs met.
  • Activity Level: Active fish might stress more sedentary species.
  • Water Parameters: Ensure all species have similar requirements for pH, temperature, and hardness.
  • Temperament: Aggressive fish might not be suitable with peaceful ones.

Do you have any experience with fish that harmonize with each other?

4. Ideal Stocking Densities for Different Fish Breeds

Stocking density refers to the number of fish per unit of water volume. Overstocking can lead to stress, disease, and poor water quality.

  • General Rule: A common guideline is 0.5 pound of adult harvest fish per gallon of water. However, this is a rough estimate, and the specific needs of fish and the capacity of the filtration system should be considered.
  • You can also start with large amounts of fry and eat them as they grow. At the end you will end up with a few giant specimens.
  • Aquaponics: In aquaponic systems, stocking density might be higher, but this depends on the efficiency of the plant filtration and the species in question.

5. Response of Fish to Environmental Changes

Fish are sensitive to fast environmental changes, and sudden shifts can be stressful or lethal.

  • Temperature: Rapid changes can shock fish. It's essential to acclimate fish slowly when introducing them to a new tank.
  • pH and Hardness: Sudden shifts can affect fish health. Regular monitoring and adjustments are crucial but usually the aquaponics system will do the work and regulate itself.
  • Lighting: Many fish prefer a consistent day/night cycle. Sudden, bright light can be stressful but sometimes unavoidable with many LED lights.
  • Water Quality: High levels of ammonia and nitrite can be harmful. Regular water testing at the beginning ensures fish health and water changes can help maintain a healthy environment in worst case scenarios.

With eating meat and fish also comes the responsibility of ensuring the fish life ends as pain and stress free as possible.


Harvesting and Handling Fish

1. Determining the Right Time to Harvest Fish

  • Size and Age: For many fish, reaching a certain size or age is a primary determinant for harvest. For example, tilapia is often harvested when they reach a weight of 1 to 2 pounds.
  • Market Demand: The demand for specific sizes or weights might influence harvest timing.
  • Health and Quality: Only healthy fish should be harvested. Signs of disease or stress might indicate that conditions aren't ideal for harvesting.

2. Techniques to Humanely End a Fish's Life

  1. Percussive Stunning: A sharp but powerful blow to the head with a round and thick wood or a hammer directly on the area where the brain is can effectively and humanely make a fish lose consciousness.
  2. If the fish eye starts rolling behind you know you did it right. Sometimes the fish will start shaking like an epileptic seizure but the fish still lost consciousness. If the fish still moves normally, hit it on the head again. 
  3. While the fish has lost its consciousness, take a sharp knife and stab into the heart. It's located at the bottom of the fish between the chest fins. After that you cut the gills so it can bleed out. Then you stab into the brain right above the eyes. Finally you should also cut the spine right behind the head to ensure a pain free quick death. Some fish like big snake heads are very hard to kill with the first blow to the head and require some practice.

Another method of humane killing is Ice Slurry: Immersing fish in a mixture of crushed ice and water can reduce their metabolic rate, leading to unconsciousness and death. This method is more humane with ice water. Proceed with point III.


Lastly you can also use carbonated water as the fish will lose consciousness quickly

because the blood flows from the gills directly to the brain. Continue with point III.


If you are sure the fish is dead you can start cleaning the fish for eating.


3. Processing and Dressing Fish for Consumption

  1. Scaling: Scales are removed using a scaler or the back of a knife.
  2. Gutting: A cut is made from the vent to the head, and the internal organs are removed. The cavity should be rinsed to remove any residue. Beware cutting into the gall bladder, which can leak its bitter taste on the fish. 
  3. Fileting: The flesh is cut away from the bones, resulting in boneless pieces of fish.
  4. Steaking: For larger fish, cross-sectional cuts are made, resulting in fish steaks with a portion of the backbone. 
  5. Bonefree: With tweezers you can remove any remaining bones.

4. Storing and Preserving Harvested Fish

  • Refrigeration: Fish should be stored at temperatures just above freezing (32°F or 0°C) and consumed within a few days.
  • Freezing: For longer storage, fish can be frozen. It's best to vacuum seal them to prevent freezer burn.
  • Smoking: Smoking fish can add flavor and extend shelf life.
  • Canning: Fish can be preserved by canning, but it's essential to follow safe canning practices to prevent foodborne illnesses.
  • Drying: In some cultures, fish is dried in the sun with salt or in dehydrators for preservation.

5. Tools and Equipment for Fish Handling

  1. Nets: Used to capture and transport fish.
  2. Fish Bins/Buckets: For holding fish after capture.
  3. Knives: For gutting, fileting, and scaling.
  4. Stick or Hammer: To hit the fish unconscious.
  5. Scalers: Tools specifically designed to remove fish scales.
  6. Opt Gloves: To protect hands and ensure a better grip.
  7. Chopping Boards: Preferably ones that are easy to clean and disinfect.
  8. Ice Chests or Coolers: To store fish at low temperatures immediately after harvesting.

When handling fish, it's essential to maintain cleanliness and ensure tools are sharp. This not only ensures the quality and safety of the fish but also respects the life of the animal by processing it efficiently and humanely.