Aquaculture in aquaponics systems is based on recirculating systems (RAS), which circulate the process water and purify it through a filtration system. Filtration typically consists of mechanical cleaning and an aerobic biofilter, often in the form of a moving bed bioreactor (MBBR).
As in conventional aquaculture, in aquaponics the fish are divided into age cohorts and sorted by size during cultivation to ensure uniform growth.
A key difference between aquaponics and traditional aquaculture is the lower stocking density. While conventional systems typically require stocking densities of over 100 kg per cubic meter, aquaponics uses approximately 40 to 60 kg. This lower density promotes fish welfare, enables more species-appropriate husbandry, and facilitates stable system operation, as it is less heavily loaded with nutrients and solids.
Another difference is the absence of disinfection through ozone or UV clarification, which are used in conventional aquaculture. In aquaponics, natural microbiology is deliberately used to maintain the biotope character. This approach strengthens the fish's immune system and makes them more resistant to disease, whereas in conventional systems, disinfection tends to weaken the fish's immune system.
Depending on the fish species, adapting aquaculture may be beneficial. For trout, flow channels that mimic natural flowing waters are often used, while tilapia are often kept in round plastic tanks that provide a suitable environment.
Je nach kultivierter Fischart kann es sinnvoll sein, den Fisch– und Pflanzenkreislauf voneinander zu trennen. In einem entkoppelten System bleibt das Fischprozesswasser sauber und der Pflanzenkreislauf kann deutlich nährstoffreicher gestaltet werden. Dies ist besonders relevant bei empfindlichen Fischen wie Forellen, die kühles Wasser bevorzugen. Würde das Wasser durch das Gewächshaus geleitet, würde es sich zu stark aufwärmen.
Another advantage of decoupling is that the water quality in each circuit can be specifically tailored to the respective culture. Plants generally prefer a slightly lower pH than most fish. Furthermore, in decoupled systems, additional nutrients such as mineral micronutrients can be added without affecting the fish.
Various fish species are used in aquaponics, and not only edible fish are suitable. The table provides an overview of the fish species, their requirements, and their suitability for use in aquaponics systems.
| Fish species | Temperature | Fattening period | Feed | Difficulty | Special features |
|---|---|---|---|---|---|
| Non-native fish | |||||
| Tilapia Oreochromis niloticus | 24–29 °C | 8–10 months | plant based | 1 | Mouthbrooders, very robust, social |
| African Catfish Clarias gariepinus | 26–29 °C | 6–9 months | both | 2 | Robust, capable of breathing air thanks to lung organ |
| Native fish | |||||
| Euroean Catfish Silurus glanis | 22–26 °C | 9–12 months | both | 2 | Robust, easy to keep |
| Schleie Tinca tinca | 20–26 °C | 16–36 Monate | both | 1 | Robust, easy to keep |
| Carp and Grass Carp Cyprinus carpio, Ctenopharyngodon idella | 20–25 °C | 10–16 months | both | 3 | Traditional fish, robust, social |
| Trout (or other salmonids, such as char) Salmo trutta u.a. | < 18 °C | 10–36 months / 300 g bis 2,5 kg | animal based | 4 | Demanding in water quality, oxygen content, feeding |
| Sturgeon Acipenseridae | 18–22 °C | 24–36 months / 3 kg bis ca. 8–15 kg | animal based | 5 | Long fattening period, caviar production only after about 5 years |
| Pike perch Sander lucioperca |
18–22 °C | 12–18 months | animal based | 6 | Difficult adaptation to dry food, difficult rearing of young animals |
| Zierfische | |||||
| Goldfisch Carassius auratus | 18–24 °C | no fattening | plant based | 2 | Robust, low demands, also suitable for small systems |
| Koi carp Cyprinus carpio forma koi | 18–22 °C | no fattening | both | 3 | Very sensitive to water quality fluctuations |
Aquaponics systems increasingly use automated systems to monitor and analyze water quality, nutrient supply, and temperature. This also applies to aquaculture. Sensors continuously collect data that is used to optimally adjust conditions. Automated feeding systems administer precisely the right amounts of feed, reducing manual labor. Daily effort can thus be reduced to a minimum, so that apart from restocking, harvesting, sorting, and cleaning, essentially only daily checks are required.
Gelderner Straße 139
47661 Issum
info@aquaponik-manufaktur.de
Gelderner Straße 139
47661 Issum
info@aquaponik-manufaktur.de