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There are three catfish farmer companies in the Silgen team, each with a special expertise in different technologies. Ahrenhorster uses fully intensive technologies, Aranyponty operates a full-scale pond-based fish farm system, and G2O is a pioneer for implementing the tank-by-pond hybrid system in practice. Their knowledge and experience lend the Silgen team leading expertise in earthen pond, net cage, intensive, and hybrid technologies as well.


Intensive Silgen technology means that catfish production is carried out in an indoor, fully controlled environment, and is not dependent on climate or other external factors. This technology allows catfish production to take place anywhere in terms of geographical location but requires advanced infrastructure and precise control. The investment in intensive Silgen farming technology is offset by high productivity and fully uniform product specifications all-year round.




The Silgen intensive technology model farm is located in the Lower Saxony Badbergen-Vehs near Osnabrück, on the former farm of the family Otto-Lübker, where catfish has been produced since 1993. Thanks to the combination of experience and state-of-the-art technologies, Ahrenhorster can produce currently more than 100 tons catfish per year.


The semi-intensive Silgen technology can be divided into two different approaches: earthen pond and net cages systems.


Type of facilities: Earthen and lined ponds


      • Advantages: Earthen pond and lined pond type wels farming requires much less investment than intensive systems. Old carp ponds can be easily converted into wels ponds with little modification. Due to the low fish density compared to intensive systems, the likelihood of disease is lower.
      • Disadvantages: Handling of fish, as harvesting, grading, disease treatment is more complicated and needs more manpower. In addition, continuous (~weekly) uniform fish supply to market is not as easy as in case of cage or RAS farm systems: Earthen pond only allows for seasonal production (April to October). 

Net cages

      • Advantages: The cages can be easily and arbitrarily installed in ponds or lakes that are at least 2 m deep, slow-flowing rivers, and irrigation canals. Harvesting and handling of fish in cages is easy. Investment costs compared to RAS are small.
      • Disadvantages: If the cages are installed in shallower ponds, they require constant aeration and a slow movement of water. The cage mesh should be cleaned at a frequency dependent on the water quality so that water can easily pass between the outside and inside. Cages also only allow seasonal production (April to October).



The Silgen semi-intensive technology model farm is located at Retimajor, Hungary, approximately 100 km southwest of Budapest. Currently they work on over 1.500 hectares of fishponds, with an annual production of around 1.500 tons of commercial size fish. The system is currently made up of 12 large ponds (10-70 hectares each) and 16 small ponds (1-5 hectares each) as well as 21 wintering/storage ponds. There is full-scale fish farming in the Retimajor farm. Fish breeds include carp, bighead and silver carp, grass carp, pike, catfish, pikeperch, tench, as well as different types of goldfish from among ornamental fish. About 100 million fish larvae are hatched in the hatchery annually. The semi-intensive farming methods are augmented with intensive facilities mainly for hatching and juveniles growth. 



Tank-by-pond could be explained as open-air RAS, where mechanical and biological filtration is performed by the pond with simultaneous aquaculture practice. Tank-by-pond systems can be built in fish farms where there is enough ground land to accommodate the tanks to be placed alongside adequately sized natural waters. Most pond farms possess some ponds that are disused or function with reduced capacity. The resource efficiency of tank-by-pond systems enable their installation using only a part of existing ponds: production capacity per surface in tank-by-pond systems can reach 500 times that of earthen pond aquacultures.

Tanks can be positioned next to the any water body with suitable water parameters for wels farming (river, lake, ground water), the scale of tank-by-pond systems should be sized according to the pond size and other environmental factors determining the filtration capacity of the pond. The newly developed hybrid system thus combines particular advantages of both intensive and semi-intensive technologies, making it an excellent choice in certain environmental and topological conditions.




During the Silgen project, a tank-by-pond pilot system for catfish production has been built at the fish farm Žabnik (Slovenia), which was originally a carp and trout farm owned by the company G2O. The farm is currently composed from 4 earthen ponds with total surface of 2 ha, and 1 tank-by-pond unit with volume of 500 m3. Annual production of the farm is 10-15 tons of cyprinids and carnivorous species. The feeding is performed with extruded feed (no use of grains), with use of aeration and monitoring.

The model tank-by-pond system was built on the location of the previous wintering pond with water surface of approximately 250 m2, coupled with a 0,2-ha pond.

The Silgen fish farming technology is currently available as product (consultation, environmental resource assessment, farm design, high performance hybrid, feed, quality control system, brand, production and commercial support). If you are interested, please contact us!

The Silgen fish farming technology is currently available as product (consultation, environmental resource assessment, farm design, high performance hybrid, feed, quality control system, brand, production and commercial support). If you are interested, please contact us!