The Aquaponics Paradox

 Aquaponics is the combination of aquaculture and hydroponics technology to grow fish and crops together.

While aquaponics provides the added advantage of fish as a byproduct, it also introduces a host of new challenges that the potential farmer would face through the maintenance cycle of the system’s existence which includes some understanding of physics, chemistry and biology to solidify its theory and functionality.

The discipline nature of aquaponics may make it appealing towards potential farmers, yet that same aspect may also make an aquaponics system challenging to implement and manage.

While the internet provides a host of information regarding aquaponics systems designs and setups, very little is said about its maintenance operations based on fish and crops management, as well as other factors that affect the smooth running operations of such systems based on where these systems are setup.

As such, many first timers find themselves stuck along the way not knowing what to do next.

It is one thing to build a system, and yet, it’s another to maintain that system.  Just because you built it doesn’t mean that you can run it.


Things To Think About Before You Setup Your System

There are many reasons as to why one would be interested in setting up an aquaponics system. Some might just want to feel the experience, while others might be thinking about a commercial approach.  In either case the principles remains the same.


  • Power Supply: Electricity is an essential component of the system’s budget and functionality, so choose the irrigation pumps and oxygen pumps wisely.  A backup power source is essential in case the primary power goes offline.  Uninterruptible Power Supply (UPS) can run the oxygen pumps as they consume low wattage. Solar or Wind Power may also be considered in areas that are off-grid or remote.


  • Water Source:  Water is an essential part of any aquaponics system.  It is the medium through which all nutrients are transported to the plants, and its where the fish live as well.  Before setting up your system, verify that you have a reliable water source, and test the water’s salinity level.  If the water is too salty it will have a negative effect on your plants.  Also ensure that your water source does not contain chlorine, as this will kill the beneficial bacteria as well as the fish.



It is imperative to test the pH of the water source periodically.  If pH keeps changing, then you will have to set-up a separate tank to correct the pH to that of the pond before topping the pond up because fish are sensitive to sudden pH changes.

Harvest your rain water if possible, as this is the best quality water source you could possibly have for your aquaponics system.

Remember that concrete water tanks, or ponds leach out toxins that gradually adjust the pH of your water upwards.

It is important to maintain the correct pH range at all times as long as the system is stable.

In a newly established system, the pH will bounce up and down, in many cases this is normal.  Let it gradually settle down to the desired 6.5 – 7.5 range on its own.  Any attempts to try and correct this problem will most likely be unsuccessful.


  • Choose Your Plants Wisely: In the early stages of your Aquaponics System, plants might not have adequate nutrients to grow well, however, with time the system gets established.  When the system is not well established avoid planting heavy nutrient feeding plants as they will experience deficiencies right away.  Start off with non-fruiting small plants such as herbs.


Not all plants will do well in aquaponics.  Some plants will do well with direct seeding, and other plants might not do well when transplanted from nursery.


When growing for commercial purposes, check the market first before deciding what to plant.  As the system gets established, try out different plants and see how they respond to the system.  It is worth noting that different crops in your system will require different amounts of nutrients at different stages of growth thereby experiencing different nutrient deficiency symptoms.

Below the Strawberry crop is showing Magnesium Deficiency while Basil is showing Calcium Deficiency even though they are growing on one system and vertical pipe.


It is important to stagger your planting as to avoid harvesting all crops at the same time from the same pond.  Remember that the fish rely on the plants to clean up the water.  Mix short and long term crops if necessary.

Below is a case of staggered production ( not all the vertical towers have crops).


  • Managing Pests: Aquaponics Systems are not immune to pest attacks, they also face challenges experienced in other methods of farming. As such, regular scouting for pests is essential.  It is important to research and find institutions that practice Integrated Pest Management to provide solutions to your future challenges, and at an early stage.

We are not talking only about common pests such as leaf miner, aphids, thrips, white-flies, spider mites and diamond-back moth but also slugs and snails that may come knocking.

Understanding how to deal with these pests in a natural way without use of synthetic pesticides is paramount.

  • Select The Appropriate Fish: Different species of fish will thrive differently in different climatic conditions.  Check your area and adopt the right variety for successful grow out.

In Africa, it is easy to get quality fingerlings for Nile Tilapia and Cat fish.

Your choice of fish may also be determined by market dynamics. Growing fish that is in demand pays off if your intention is to make income from aquaponics.

Do not over stock your ponds, get to learn the ropes first by understanding the system’s threshold and scalability.

Learn how to troubleshoot and correct problems as they arise before deciding to push the envelope.

DO NOT add too many fish to a pond that already has fish as this will shock and overload the bio-filter.  Instead, try a little at a time whilst testing the ammonia, and nitrite levels.

It is important to keep your ponds clean to avoid bacterial and other diseases.

Clean the ponds as often as required by removing the muck that settles at the bottom of the pond in order to maintain healthy and stress free fish.