Aquaponics, or the Aquaponic System, is a hydroponic system where we integrate fish bred under captivity or in confinement, with hydroponics.

By using this system, we can produce not only vegetables, but also fishes.

The basic system is very simple, as the various nutrients which the plants need, are supplied by the water in which the fishes breed and defecate.   In the process of taking up the nutrients, the plants purify the water.

This is a mutually beneficial environment which reproduces the Nature conditions, with the advantage of being under our total control.

The aquaponic system is ideal to be mantained in homes and apartments.

It can also be established in large comercial units, where one can generate profits not only from fishes but also from vegetables.

There are two distinct aquaponic systems.

In the first one, fish feces are mantained dissolved or in suspension in  water, which is then circulated through a Biofilter, which in reality is a kind of Biodigester, where two biodigestions take place.

The first biodigestion takes place at the upper level of the biofilter, in an aerobic surrounding.   Here, aerobic bacteria convert the nitrogen in form of ammonia (NH3), into nitrates.

This ammonia (NH3) is expelled by the fishes' gills.

In contact with water, part of this ammonia reacts, forming ammoniac or ammonium hydroxide (NH4OH).

The second biodigestion takes place at the botton of the Biofilter, in an anaerobic surrounding, where fish feces are converted into various mineral and organic-mineral salts.

The salts resulting from both biodecompositions, dissolve and ionize in water, and are absorbed by plants, producing clean water, free of dissolved salts and various impurities, which then returns to the fish rearing tanks.

In the second system, fish feces are separated from water by a mechanical filtering operation, and the water full of ammonia (NH3) and some ammoniac ( NH4OH) which was originated from ammonia (NH3) emited by fishes, passes through a biofilter.

In this biofilter the ammonia is transformed into nitrates by the action of aerobic bacteria, and these nitrates, dissolved and ionized in water, are absorbed by plants.

Thus, we get a pure water, which is returned to the fish rearing tanks.

Fish feces retained in the machanical filters can be used in two different ways.

The simpler one, is to use them for the production of organic compost, by aerobic decomposition.   This compost can be used to fertilize soils.

The other way of using fish feces, is by treating them in Anaerobic Biodigesters, and using the resulting Biofertilizer in the hydroponic system, or in the fertilization of soils as above.

We can note that in this system the only losses we have is the water used by plants and fishes for their development, the water lost through evaporetion on the surface of the rearing tanks and culture benches, and the water lost by plants transpiration.

Though it seems to be a very simple system, it is quite complex, as we are working with two different biomasses that are completly antagonistic, on the one hand, the fish biomass (essentially aquatic), and on the other, the plant biomass (terrestrial).

To mantain these two biomasses in equilibrium is a difficult task, that demands spacialized knowledge and research.

So, to build such a system on a commercial basis, proficient technical support is advisable.

Besides, it is also advisable the reading and studying of books which provide basic knowledge of hydroponics, as this technology is based in scientific knowledge, extracted and developed from thousand-year-old agricultural practices.

The integration of pure Organic Hydroponics with Aquaculture, constitutes a mini closed echological system, environmentally friendly, where all elements that participate in the process are recovered and recycled.