Common Fish in Aquaponics

Fish tank filled with Koi

Common Fish in Aquaponics

Common Fish in Aquaponics

August 25, 2021

There are a few things that need to be considered when choosing the right type of fish for your system. While there may be several suitable options, from decorative koi to consumable breeds and freshwater shrimp, it’s important to make sure you understand the good, the bad and the ugly when caring for each type of fish.

Here at Ichthys, we like to use the basic principle: Use fish with the least amount of cost in relation to production. This is often the type of fish that naturally occur in your area. We have decided to compile a short guide for you where we compare the different breeds to assist you in making the best decision for you and your system.

What are some common types of fish used in Aquaponics?

Man holding a rainbow trout as a common fish used in aquaponics

Rainbow Trout

The Oncorhynchus mykiss is commonly found in places with a cooler climate. The ideal temperature for optimal growth rate is 18oC and they grow fairly slowly. Fingerlings take approximately 6 months to reach 100g.  As much as the idea of trout farming sounds profitable and fairly easy, we have to warn you that trout can be very finicky and require very specific conditions to thrive.


  • They can be sold for a fair price on the market.
  • Salmonoid Family – market conscious.
  • High in omega 3’s and make for a great tasting meal.


  • Prefer cooler climates: this could become problematic during South African summers.
  • Your choice of plants is restricted as not all plants can grow in cooler water.
  • High requirements of dissolved oxygen.


CO2 DO Temp NH3 NH4 NO3 Salinity
<20ppm >6ppm 12-25 <0.4 <0.4 <70ppm <15ppt
Catfish from an Aquaponics System


We LOVE farming catfish on our farms. At first glance, catfish seems to be produced as a cheap protein for the lower-income market. However, it is a versatile protein source that can be quite suitable for more up-market consumers if processed, packaged and marketed correctly.


  • Quite a hardy species that can tolerate a range of DO levels, temperature and pH.
  • Easy to care for and breed.
  • They have a variable diet from plants to bugs, small fish and pellets.
  • Good tasting fish.
  • Fast growth time.
  • High stocking densities.
  • They require a lower protein diet than trout that require higher levels of protein in their diet.


  • Must ensure that the same size fish are kept together to avoid cannibalism.

Sharptooth Catfish

 The South African indigenous Sharptooth Catfish is considered to be the species with the greatest mass production potential in South Africa.

CO2 DO Temp NH3 NH4 NO3 Salinity
<15ppm >3ppm 15-30 <0.4 <0.4 <200ppm <5ppt



This is a species of catfish and they are fast becoming one of the most popular freshwater fish being sold in restaurants. Therefore, making it an important fish in the international food market. Due to its fast growth rate and delicious white flesh, this species is becoming quite popular amongst aquaponic farmers.

CO2 DO Temp NH3 NH4 NO3 Salinity
<15ppm >1ppm 20-30 <0.4 <0.4 <200ppm <5ppt
Tilapia fully grown from an aquaponics system


The number one contender, the Tilapia is the most popular fish used in aquaponic farming worldwide.


  • Fast growth rate.
  • Fairly sturdy and adaptable.
  • Quick reproduction rate.
  • Don’t require high levels of dissolved oxygen.


  • Warmer water is required – sometimes may need to heat your water.
  • Their fast reproductive rate can become problematic in a smaller system.


The Niloticus tilapia is part of the Oreachromis Tilapia family. This means they are mouthbrooders and have the most amount of genetic research behind their name. In optimal conditions of temperatures of 25oC+, it is possible to achieve a growth of up to 500g in 6 months from fingerlings.

CO2 DO Temp NH3 NH4 NO3 Salinity
<45ppm >4ppm 20-30 <2 <2 <200ppm <20ppt



The Mossambicus tilapia, also known as the blue kurper, belong to the same family as the Niloticus and are native to Southern Africa. It is a slower growing fish, however, more tolerant to colder water. We recommend using this type of tilapia when the niloticus is not permitted to be farmed in your area.

CO2 DO Temp NH3 NH4 NO3 Salinity
<45ppm >4ppm 15-30 <2 <2 <200ppm <20ppt


Coptodon Rendalli

The rendalli is a great fish to farm in your aquaponic system. Being part of the coptodon family means that they are substrate layers and they will lay their eggs on the floor of the tank. Its round shape is great for a much larger filet to mass ratio of 50%.

CO2 DO Temp NH3 NH4 NO3 Salinity
<45ppm >4ppm 15-30 <2 <2 <200ppm <20ppt
Koi Fish as a common fish type in aquaponics

Koi & Goldfish

If you are more of the decorative type, then these fish are perfect for you. They are easy to take care of and Koi can have a long lifespan. When it comes to decorative fish, the main disadvantage is not being able to eat your fish.


  • Beautiful ornamental fish that can also make for great pets!
  • Hardy fish that tolerate pH ranges and a range of temperatures.


  • Koi can produce excess waste that might lead to additional tank cleans.
  • Goldfish cannot be mixed with other fish in the tank.

Hopefully, you now have a better idea about the common types of fish used in aquaponic farms. When it comes to choosing your fish, make sure to consider what you want out of your system as well as your location and climate. You don’t want to spend excess cash on trying to replicate a climate that you don’t experience in your area. Therefore, if you want some advice about what fish would suit your specific tank then make sure to book 15 mins with Mark or a consultation with us here at Ichthys.