The Ultimate Guide To The Best Fish For Aquaponics

Choosing the best fish for aquaponics will benefit you as fish play a significant role in any aquaponic setup. Fish complement the hydroponic part of an aquaponic system by producing ammonia waste into the water that plants in the hydroponic part use for their growth. The fish’s waste can be harmful to plants in the system if it is not converted to nutrients. Bacteria act on the fish waste and convert it into nitrates and nitrites. Fish which are highly resistant to high amounts of nitrites are ideal for aquaponics. Therefore, it is equally essential that you choose the best fish for small aquaponics and the best fish for indoor aquaponics that will best suit your setup.

Factors To Consider When Choosing Fish For Your Aquaponics System

It is essential to analyze your aquaponics setup before choosing any fish type that fits your system. Below are some factors that will guide you make a simple but essential analysis of which fish is ideal for your system.


How large is your system?

Large fish for your commercial purposes may not do well in a small system. The best fish for aquaponics you choose must fit the overall size of your operation.


Any fish type has its breeding conditions. Some fish breed well in cooler conditions compared to others. Fish in your aquaponic system may fail to breed successfully if you don’t regulate the water temperature to their breeding conditions.

Space for your system

You need to ensure that the space your system occupies fits the type of fish you intend to rear in your system. Small fish can be reared successfully in an indoor aquaponic system.

Temperature compatibility

Some fish can survive temperature and environmental fluctuations more than others. Some fish need to be in habitats with little changes in the environment. Consider fish that are highly adaptable to fluctuating environments.

Tilapia Aquaponics


Some fish are not available in the US. Tilapia is the most common fish available in most parts of the world. Consider the best fish for aquaponics available in your area. Some fish species may be illegal in your country.

Filtration of your system

Your fish tank has to have a good filtration capacity to accommodate a relatively good number of best fish for small aquaponics. A good ratio of your tank’s capacity to the number of fish ensures a balance between the fish’s requirements and the plants’. A highly populated fish tank will most likely disrupt oxygen concentration in the water.

Fish food

The type of fish you choose for your system requires the correct balance of carbohydrates, fats, vitamins, proteins to flourish and give the required nutrients to your plants. You can acquire fish food with the correct amount of nutrients or homemade fish food that you can scale your nutrients accordingly. Although homemade fish food can be cheaper, it may lack the balanced nutrients needed by the fish.

What Are The Best Fish For A Small Aquaponics System?

The best fish for aquaponics may be small fish that will guarantee they fit in your tank even after maturing. Small fish that don’t grow too large will ensure your fish tank is not overcrowded. Below are some small fish species you might want to consider for your small aquaponic system.

Tetra fish

Tetra fish are quite a popular and diverse type of freshwater fish. It has many underlying species, including Diamond, cardinal, rainbow, bloodfin, emperor, lemon, ember, and neon tetras. Tetra fish grow up to 2.5 inches long and are ideal for medium-capacity tanks. They don’t usually blend well with other fish species. Tetra fish survive in water with 5 to 8 pH levels and warmer temperatures of 68F to 82F. Tetra fish are not edible and only valued as pet fish. Ease of raising and breeding are some of the advantages of tetra fish.


Guppy is very hard and the best fish for small aquaponics that may sometimes get over-concentrated with nutrients. Guppies exist in many different species; Endler and rainbow guppy are among some of the species. Guppies are available almost everywhere globally; hence they are a great choice for an aquaponic system. Guppy fish best survive in temperatures between 72F to 78F and a pH of 6.7 to 8.5. They tolerate minimal fluctuations in the water conditions. Guppy fish grow up to 2.4 inches long. An advantage of guppies is that they are edible, but their small size hinders effective cleaning of their insides.


Goldfish produce high amounts of waste, ideal for a typical aquaponic system. High amounts of waste mean high nutrients for aquaponic plants. Depending on the condition you keep them in, goldfish can grow up to 12 inches long. When kept in a pond, they tend to get very big. They are hardy; hence they can survive in fluctuating environments. Their survival is best encouraged at temperatures of 23oC to 50oC and pH of between 7 to 8.4. An advantage of goldfish is that they eat a wide variety of fish food, including vegetables.

Goldfish Aquaponics

What Are The Best Fish For A Large Aquaponics System?

An extensive aquaponics system requires fish that can grow large. Below are some of the best fish that can grow in large tanks.


This type of fish is prevalent around the world. They are used in many groceries and restaurants because they are very edible. Tilapia grow up to 8 inches long and are easy to rear and breed on a small or large scale. They mature quite quickly as they can be harvested when they reach six months. They survive best in temperatures between 80oF and 85oF and a water pH of 6 to 9. Tilapia are hardy and can withstand fluctuating environments, making them ideal for aquaponic systems. Their advantage is that they reproduce quickly, hence ideal for larger hydroponic systems. Some of their disadvantages are that they require warmer temperatures.


Like tilapia, catfish survive in warmer temperatures, although they can do well in colder temperatures. They survive in temperatures between 65oF and 90oF and a pH range of 7 to 8. One catfish uses 8 gallons of water. Catfish feed on proteins, pallets, and homemade fish food. Their hardy nature makes them survive in fluctuating pH and temperatures. They are easy to raise and breed. Catfish feed mostly at the bottom of tanks; hence ideal for large systems with lengthy horizontal space. Their growth rate is high and can be harvested when they reach three months. A major disadvantage of catfish is that they require high protein food. They are also delicate since they do not have scales.


Koi are very large fish and can live up to 30 years. When fully matured, they can attain lengths of more than three feet. Their large nature makes them ideal for your large systems. More than five mature koi fish need more than 1000 gallons of water in your aquaponics tank. Koi survive in temperatures between 65oF and 78oF and a pH of 6.5 to 8. They can eat a variety of fish food, including vegetables. Koi are very resistant to diseases and survive fluctuating temperatures. A major disadvantage of koi fish is that they produce excess waste as they grow old; hence they require frequent cleaning to keep your system efficient.

Koi Aquaponics

What Are The Best Fish For An Indoor Aquaponics System?

An indoor system is attractive to your indoor space and secure from outdoor inconveniences. Choosing the best fish for an indoor aquaponics system requires understanding your indoor space as it is always not very vast. An indoor system requires a small to medium-sized type of fish.


The cute nature of these little-sized species makes them ideal for your ultimate indoor purposes. They are not edible, but they are the best fish for indoor aquaponics. They are very easy to care for and rear since they can live for more than five years. A major advantage of goldfish is that there are many species of goldfish to choose from and incorporate into your system.


Guppy fish are very small, making them ideal for your indoor aquaponic preferences. They are treated as pet fish because they are gorgeous. Guppy fish have great market value, and you can rear them for commercial needs.


Crayfish are edible because of their meaty tail. They are best to survive in water with a pH of 7 to 8.5 and temperature ranging from 70oF to 75oF. Their major disadvantage is that they can take up to four years to fully mature.


It would be best to do a little digging to choose the best fish for the aquaponic system. This guide has outlined several types of fish that best suit your small, large, or indoor aquaponic system. You need to consider the characteristics of your system then move forward to the best fish for it. Small systems require small fish to avoid the fish overcrowding your tank and releasing excess waste. Tilapia and koi are large fish for larger systems as they grow faster and larger.

Happy rearing!

aquaponics experts

Welcome to The Aquaponics Guide

Hello! We are the Johnsons and the faces of The Aquaponics Guide. We have been avid gardeners for many years and growing our own food is one of our key priorities. We have found sustainable Aquaponics farming to be a life changer, which is the reason we have created The Aquaponics Guide. 

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