Our location in Porta Westfalica.

Location: Porta Westfalica

We are Kaiserzander In
Porta Westfalica.

Since fish is a valuable foodstuff, the goal of producing zander in indoor fish farms can meet the population's growing demand for regionality and "clean" food. Against this background, glammeier+john aquakultur GbR was founded in 2012, which was converted into a GmbH & Co. KG in 2019.

– Pool volume: approx. 1,000m³
– Stocking:  ~30,000 pcs/quarter
– Full stocking:  max. 60t fish
– Annual production:  ~100t fish
– Recirculation rate/hr: 1.5 – 2.5 hrs
– Water exchange/day: 3 – 10%

Once the supply of stocking fish for a large fattening facility could be guaranteed, after exhaustive research and the conversion of the aquaculture facility in Niederlangen, construction in Porta Westfalica began at the end of 2020. After four months of construction, the system technology and the pools were installed at the beginning of 2021 and gradually put into operation. Only when the technology and biology were fully operational did the first 30,000 zander seedlings move into the new facility in summer 2021.

Our recirculation system consists of holding tanks as well as biological and mechanical cleaning cycles. When fish are kept, dissolved and particulate substances foul the water (unused feed and excrement). For optimal environmental conditions, the contaminated water is cleaned mechanically and biologically, tempered, enriched with oxygen and then returned to the fish population. Particulate components can be removed from the holding water by various technologies such as perforated drum filters, flotation or microfiltration. This separated matter can either be applied to the field as farm fertilizer or used in a biogas plant.

We achieve optimal husbandry conditions and absolute fish well-being through constant monitoring of all relevant parameters. The system is monitored 24/7 by countless sensors. These can be monitored and controlled from outside the building. The measurements of all sensors are evaluated by software in real time. In the event of deviations from target values, the control automatically regulates the conditions to restore optimal husbandry values. In principle, all parameters are based on natural conditions. With the system technology, we ensure that the natural processes are strengthened and accelerated.

In addition to the water parameters (such as oxygen content, temperature, etc.), feeding is a major influence on the health and growth of zander. The feed is optimally tailored to the needs of the zander and produced as sustainable as possible. Our food contains no preservatives and is 20% animal protein. The rest is vegetable protein. An automatic feeding system, delivers small portions directly into the tank, dispensing only as much feed as the fish will eat, to save resources, and keep the water cleaner. Since the zander is a nocturnal fish, it is fed mostly during the night hours.

We keep up to 120,000 zander of all sizes in a total of 22 tanks with a total volume of almost 1,000m³ of water. In Niederlangen, each quarter tanks can be restocked. The young fish come to Porta Westfalica at 90-100 days and weigh about 15 grams. Within 350-400 days these grow to an average of 1,000g and grow up to 50cm. At this size, the animals are sexually mature. In total, we are able to produce around 100t of zander per year. Depending on customer requirements, these are produced as stocking fish for bodies of water or as food fish of different sizes.

A set stocking density is required so that the zander does not behave territorially as a loner. The zander are comfortable in a pack or swarm. It is important that the individual groups in the tanks live together in homogeneous sizes.Larger individuals would hunt, suppress and even eat smaller members. Smaller fish would no longer be able to access the food and would be disadvantaged in terms of growth. Becaue of this, we initially stocked the tanks with juveniles of the same size. Due to genetic differences or feeding behavior, the animals grow apart in terms of size and have to be sorted at regular intervals. We have developed a gentle process for this, in which the fish are simply sucked out of the tank using a vacuum fish pump without having to be transported by hand or net. They then run through a sorting machine that was specially developed for zander and are again socialized with animals of their same size.


Our claim to rearing.

Sustainable is the maximum utilization of the resources used. We achieve this through efficient modern technology and processes. We are climate neutral.