Is Aquaponics Safe For Fish?

Aquaponics is a self-contained, mini-ecosystem where fish and plants work together to keep the system balanced. The intention is to produce vegetables and protein in a controlled environment to feed a family or neighborhood. I know that the aquaponics environment is great for the plants, but is it safe for the fish?

Aquaponics is safe for fish so long as the right species of fish is chosen to keep in the system and the conditions in the system are maintained to the fish’s needs. This includes water temperature, oxygenation and proper filtration of solid waste and dissolved toxins such as ammonia.

Because of the nature of the aquaponics system, there are only certain species of fish that are suitable for this kind of containment. In the aquaponics system, you are not only farming vegetables, but you are also farming fish. Learn more about aquaponics in my article, What is Aquaponics – The Complete Guide. As with any other livestock farming, you need to make sure the animals are kept in an environment that is both habitable and safe for them. Otherwise, you will have fatalities in your livestock and introduce disease to the system.

Tilapia aquaponics
Photo 36935074 © Komprach Sapanrat |

Problems That Face Fish In Aquaponics

Because the fish in an aquaponics system are not in their natural environment where their environment is regulated by natural processes, we need to simulate those processes mechanically.

The main factors that are problematic for fish in an aquaponics system are space, oxygenation, pH levels, solid waste removal, and dissolved waste removal from the water.

Space For Your Fish

Fish need space, space to move, feed, and breed in the aquaculture tank. Some need more than others, but this is what makes Tilapia a favorite as they are the most tolerant in this regard. However, you will still need to manage your fish numbers to prevent overcrowding and the increased toxic waste levels in the water that can result from too many fish in a small space.

Proper Water Oxygenation

The amount of oxygen in the water is proportional to the surface area of the water. The larger the surface area of the water, the more gas exchange can take place between air and water. This has implications for the size of your fish container and the amount of artificial oxygenation you will need to provide in the way of aeration pumps.

Solid waste removal

You will need to make sure that the filtrations of the water through the plants, and the subsequent filters, removes all solid waste from the water to prevent disease from gaining a foothold in the system.

If solid waste becomes an issue it can lead to your aquaponics system smelling. Learn more about how to prevent smells in my article, Do Aquaponics Systems Smell?

Dissolved waste removal

Ammonia levels in the water can build up very quickly, especially with a lot of fish in a confined space. Even a small rise in ammonia levels can be toxic to the fish. Over-crowding of fish often results in stock losses from ammonia poisoning. Your filtering processes need to adequately remove these dissolved toxins to keep them at safe levels for your fish.

pH Levels of the Water

Some fish are very sensitive to changes in the pH or acidity levels of the water. The pH level can change due to the waste products in the water from both the fish and the plants. pH must be monitored carefully to ensure the environment is healthy for the fish.

To keep your fish happy and healthy, you will need to make sure that each of these metrics are monitored carefully on a daily basis.

Challenges such as cold weather and erratic electricity supply may affect your choice of fish, the size of the fish container, and whether your fish enclosure needs to be in a self-contained tunnel or not.

Photo 15283578 © Xunbin Pan |

Type Of Fish For Aquaponics

If you want your fish stocks to thrive and be comfortable in your aquaponics systems, you need to choose the type of fish carefully.

Not all fish are suited to this type of environment and do not do well in the space constraints or lack of other natural components that they have adapted to in their natural habitat.

The most common fish to use for aquaponics are freshwater fish, but only certain types of freshwater fish can handle being housed in an aquaponics system.

Saltwater fish can be run in an aquaponics system, but then it is differentiated as saltwater aquaponics, and it comes with a higher degree of difficulty, level of monitoring, and equipment needed to run the operation.

The types of freshwater fish that are suitable for aquaponics are ones that are hardy and can function well in large groups. Some fish require the water to be warm, which will require you to have water heating methods to keep the fish healthy and happy.

Other fish are not too fussy about the temperature and will do fine in cooler water. These types of fish would be better where electricity is a problem to maintain the heat in the fish tanks.

Among the warm water fish, the Tilapia is the fish that is most commonly used in both home-based and commercial aquaponics operations. This is because Tilapia are a good eating fish, they can tolerate smaller spaces and are less susceptible to changes in the water condition.

The best warm water fish for aquaponics

  • Tilapia
  • Barramundi
  • Eel-tailed Catfish
  • Silver Perch
  • Jade Perch
  • Murray Cod

Most common cold-water fish for aquaponics

  • Bluegill
  • Catfish
  • Channel Catfish
  • Common Carp
  • Rainbow Trout
  • Arctic Char
  • Striped Bass
  • Largemouth Bass

If you don’t want to farm fish to eat in your aquaponics system, you can use Goldfish or Koi in the fish habitat, and you can sell these fish to people as ornamental fish for their garden ponds or as pets. This could become an important source of income that could help to offset the expense of running your aquaponics system.

Fish are not the only creatures that you can keep in an aquaponics system. Crawfish and shrimp can also be raised in aquaponic systems.

The type of fish that you select must be suitable for the conditions that you have available for your aquaponics system. This includes taking into account your local weather conditions, the size of your fish container, and the capacity of your systems you have in place to monitor and maintain temperature, pH, and filtration.

The type of fish is important, but equally important are the conditions under which they will be kept. The following are the main issues that could face the fish in your aquaponics system.

aquaponic seafood
Photo 33254464 © Karel Noppe |

Keeping Aquaponic Fish Healthy

As homesteaders or people who are interested in sustainable food production, we need to be good stewards of the natural environment. This means making sure that the livestock we keep is kept in the best possible environment that caters to their needs and does not cause them distress.

Failing to do this is not only cruelty towards animals, but it also has the potential to introduce problems into the group. In aquaponics, problems with your fish will have a knock-on effect and result in problems down the line in the plants you grow.

An aquaponics system relies on all components or chains in the system operating at optimum levels to ensure a healthy system that provides maximum yield.

Aquaponics is perfectly safe for the fish, provided that certain guidelines are adhered to in order to make the conditions for the fish as natural as possible.

Final Thoughts

Aquaponics can be a rewarding, successful, and sustainable method of growing vegetables and producing protein in a self-contained system.

Aquaponics can help to increase the food production of a relatively small area and can provide a sustainable protein source. However, with the fish-keeping side of aquaponics, there is a pretty steep learning curve associated with getting all the science correct and balancing and monitoring the system for changes.

You will get this right with some research and practice, and as long as your fish choice has been correct, there is no reason that your aquaponics system should not be safe for the fish. The system should not only be safe for the fish but allow them to thrive and remain healthy to make your entire system productive.

Beau McManus

I love to grow great food and eat great food. Controlling the quality and supply of my food has always been a passion.

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