What is Aquaponics

What is aquaponics?

The simplest explanation of aquaponics is that is it a combination of aquaculture (which is the farming of fish) and hydroponics (growing plants in a water based system without soil). Done correctly, the marriage of these two systems creates a natural ecosystem that is able to produce both fish and plants together in a single system with very little outside interference. This ecosystem comprises of Fish that provides waste that is an organic food source for microbes (nitrifying bacteria) that converts the ammonia from the fish waste into nitrites and then nitrates, this is then used by the plants for growth. Solids from the fish waste is intern converted into Vermicompost that also acts as a food source by the plants.

Aquaponic's Core

The four core aspects of Aquaponics


Aquaculture is the farming of aquatic organisms including fish in controlled or selected aquatic environment, with some form of intervention in the rearing process to enhance production, such as regular stocking, feeding, and the protection from predators.


Vermiculture is the process of converting decomposing vegetable or food waste into useful nutrients for plants by the means of farming worms (and microbes) which consume the waste and excrete it in the form of vermicast.


Hydroponics is the method of growing plants without soil, using mineral nutrient solutions in a water solvent, this is achieved in aquaponics by inserting fish into the system in place of artificial nutrients.

Testing and Record keeping

Testing the ammonia, nitrite, nitrate and pH levels in an aquaponics system ensures that the plants are getting the correct nutrients and the fish have clean and safe water to live in. To ensure that you have a consistent yield, records of each test needs to be recorded and monitored for drastic fluctuations.


Aquaponics vs. Hydroponics

Why Aquaponics and not Hydroponics?

A comparison


Aquaponics takes approximately 4 weeks to start by first introducing nitrifying bacteria through a process called cycling. These bacteria brake-down the ammonia from the fish waste into nutrients for the plants.

Aquaponics is far less sterile as the system is reliant on the good bacteria that breaks down the ammonia.

A comparison


In hydroponics, you add commercially formulated nutrients to your nutrient reservoir and you begin growing immediately (Faster)

Hydroponic systems tend to be fairly sterile.

Water temperature has to be kept below 21 degrees Celsius in order to prevent root-rot that thrive in warmer temperatures.

Using a flood and drain technique that cycles for around 15 to 20min in every hour. Grow beds act as a natural bio-filter and filter out all the fish waste in order to convert it into nutrients for the plans also housed within the beds.

Grow beds are typically 300mm deep and filled with pH neutral media, although deep-water culture (DWC) is also often utilised.

Aquaponics strives to be a balanced ecosystem, relying on the fish waste to feed the microbes and intern nourish the plants within the system.

Aquaponics uses 95 to 98% less water than tradition farming, because the system is a closed, reticulating circuit one never has to dump all the water unless there is a drastic problem. Only a top up of the water when needed occurs.

Using flood and drain techniques generally only flood their plants once every four to six hours. Studies have shown that this optimizes the water and fertilizer the plants need.

Hydroponics tend to use 15cm deep troughs and put pots or specially designed grow cubes with plants in them.

Hydroponics rely heavily on the exact nutrient and supplement in order to grow successfully.

Nutrients must be discarded and replaced on a very regular basis in order to address nutrient imbalances that arise with every grow cycle.

Sterilization is paramount with every part of the system. The system is extremely prone to root-rot.

Optimal pH in hydroponics is between 5.5 and 6.0

Root-Rot is virtually non-existent within aquaponics no matter what the water temperature is.

The only driving feature there is in regards to water temperature in aquaponics is the fish. Tilapia is the most common because of its exceptional growth rate but other fish are also used such as Koi, catfish and various freshwater shrimp.

The pH level in aquaponics is a compromise between the requirements of the plants and the requirements of the fish. The optimal pH is 6.8 to 7.0, levels that closely resemble that of traditional soil levels.

Ammonia levels, pH and water temp are checked on a weekly basis once the ecosystem is established in order to catch large fluctuations in the system. These fluctuations happen very seldom.

Aquaponics creates a true ecosystem and thus is considered to be 100% organic and is environmentally friendly.

A strict measurement of pH, water temperatures and Electrical Conductivity (EC) has to continually monitored to inform the grower of the nutrient solution’s concentration to optimise growth.

Hydroponics is designed for plants that can be grown in highly optimised and sterile conditions.

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