Aquaponics is known as the combination of two techniques known as aquaculture (the process of growing and harvesting fish and other aquatic organisms) and Hydroponics (the process of cultivating plants without soil). Apart from growing different kinds of plants, it is also possible to grow fish through this system without requiring a large area of fish pen. There is an assurance that the fish are high in quality and free from harmful chemicals and pollutants.
The role of the fish in aquaponics is to provide the plants with a natural kind of fertilizer. The fish excretes waste products in the form of ammonia from the metabolic processes in its body. The ammonia can be converted into its useful form, which is nitrate and the plant takes it up as a nutrient. At the same time, the plants filter the water by taking up the waste products present in it. This provides a clean environment for the fish to live in. All in all, the two survive in the system in a symbiotic manner.
As compared to aquaculture, it is a more sustainable way of breeding fish. Aquaculture is often done in large tanks that take up a huge amount of space. The disadvantage of using aquaculture is that it results to the accumulation of a large amount of waste products. Since this method requires a large tank, then a large quantity of fish is also grown. It can make the water toxic due to the high amount of waste.
In aquaponics system, the stocking level of fish can vary depending on the size of the fish tank and the amount of water in the system. In maintaining a heavy stocking density, the water quality should be checked constantly to ensure that its condition is still at its best.
Many fish species are available in the market, but only a few can survive in an aquaponics system. It is important to consider the size of the system, as well as other factors like the pH, salinity, dissolved oxygen content and the temperature of the water. Different kinds of fish thrive in different environmental conditions. Since the aquaponics system uses freshwater, it can only support the growth of freshwater fish and not marine fish.
The most commonly used freshwater fish in aquaponics is tilapia, scientific name Oreochromis niloticus. It is easy to breed. It is also fast growing and can live in a temperate environment. It is a good source of protein and is very popular in a lot of countries.
Trout, on the other hand thrives in a much cooler environment (10-20˚C). It also has a very fast growth rate and it is an important food source for humans. For recreational and aesthetic purposes, goldfish is also considered as a commonly used aquaponic fish. It is a popular aquarium fish because it is easy to take care of. If overfed, it excretes more waste, which makes them good for aquaponics.
In the aquaponic system, the fish is the main driving force of the whole system. Generally, it is where the cycle starts due to the excretion of waste products. Breeding fish in an aquaponic system may seem hard, but it is much easier as compared to aquaculture. It also has many benefits especially for people who want to earn a living from the comfort of their home.