A swimming pond with fish makes it necessary to plan comprehensively and to give the near-natural pool an appropriate level of care. If put on correctly, however, it can represent a much easier-care alternative to the swimming pool and is also gentler on the skin. However, this only applies if certain factors are taken into account.
Legal conditions
In order to be able to create and successfully maintain a swimming pond with fish, a depth of at least 1.5 meters and the largest possible volume of water are required. As a result, the pond may require a permit in some federal states. A general statement on the necessary applications and confirmations cannot therefore be made. Instead, the responsible building authority must be asked what dimensions are allowed and what must be taken into account during implementation.
size
The following applies to the size of the swimming pond: the bigger, the better. Larger amounts of water are easier to keep clean and in a healthy balance. This is also very clearly visible in lakes, for example, which, unlike small garden ponds, do not require filtering.
as Rule of thumb The rule is that the pond should have a depth of at least 1.5 meters. On the one hand, this is necessary for buoyancy and swimming; on the other hand, it also benefits the fish, which can easily be overwintered on site in ponds of such depth. An exception are koi, which should not be left in the pond during the winter.
When creating the swimming pond, you should therefore think as large as possible. This is also necessary because of the different areas in the pond, which are used for filtration on the one hand and protection for the fish on the other.
foil
A stable and robust foil should be chosen as a suitable underlay for the pond. For example, EPDM foil that is at least 1.5 millimeters thick is ideal. This can also be entered without any problems and has proven to be durable and resilient. Nevertheless, it is flexible enough to adapt well and to be comparatively easy to lay.
Areas and equipment
The swimming pond must be divided into different areas so that it can be used by humans on the one hand and as a habitat for fish on the other. A division into three sections is ideal. A swimming area, a shallower bank area for the fish and a so-called filter and regeneration zone.
The different areas each fulfill different functions and must therefore be designed differently:
Swimming area
In order not to disturb swimming, this area should be free, deep and large. The swimming area also includes safe entry and exit. Flat, non-slip steps must be created for this. A railing can also be attached as an addition. In order not to disturb the natural look of the swimming pond, the railing or the visible part of it can be made of thick branches with bark.
Bank area
A flatter and planted bank area serves the fish on the one hand as a protection zone and on the other hand as a source of food. For wintering, a depth of at least 80 centimeters should be given, which, however, can increase continuously or gradually. This also benefits the variety of plants that can be planted in the bank area. These should be of different heights and cover the widest possible range of species. On the one hand, this already creates a comprehensive, natural filter performance. Because the plants need nutrients and withdraw them from the water. The more species there are, the more different nutrients are removed.
Filter and regeneration zone
The filter and regeneration zone is used to purify the water in a targeted manner. So that neither parts of the plant nor the floor covering are whirled up, only a suitable substrate should be applied in this zone. This procedure also helps to keep the suction area of the filter clear. A floor covering made of zeolite with a thickness of at least 20 centimeters can already have a good filter effect. Because microorganisms can settle in the substrate, decompose the nutrients and thus clarify the water.
plants
Put in baskets
Experience has shown that it makes sense to put the aquatic plants in baskets and only then put them in the pond. This means that the plants can be removed easily and without much effort for winter storage and for cleaning the pond. This also makes it easier to care for the plants and reduces pollution in the water. Another advantage is that the substrate of the plants has to be used to a limited extent. This creates less mulch in the pond.
Remove damaged
Damaged parts of the plants should be removed immediately. Otherwise, decomposition processes can significantly reduce the water quality. Dead and broken parts of plants should therefore be cut cleanly and disposed of as quickly as possible.
Diverse, but economical
Several different aquatic plants make sense, as this allows a wider range of nutrients to be absorbed from the water. However, the number and mass of the plants should not get out of hand. Because this could also affect the water quality.
Flooring
Zeolite is wonderfully suitable as a floor covering for the bank and regeneration zone. In order to prevent slipping on the film, gravel mats can also be used. Both gravel and zeolite ensure that microorganisms can settle more easily. These microorganisms in turn ensure that the water is clarified. In addition, the subsoil is ideal for fish that like to bottom. Safety, cleaning and a source of food can therefore be provided by gravel and zeolite.
Filtration and purification
Even if the right floor covering and the right planting already have a cleaning effect, the swimming pond must still have a filter system. It is ideal if different levels are also available for this. A system with the right capacity and UV light to remove algae is therefore a basic requirement. Another help when cleaning swimming ponds can be a cleaning run. The water is sucked in deeper, runs through the filter system and is pumped upwards. The water can run through gravel again through a stream from top to bottom.
In this way, on the one hand, the washing up of sediments is avoided and, on the other hand, an increased cleaning performance is generated. However, even this measure cannot completely prevent sediments from being deposited. Therefore, another cleaning measure must take place regularly.
Basic cleaning
The basic cleaning involves vacuuming up sludge. The deposit can also be referred to as silt or silt. In any case, it is not a problem in small quantities, but it can lead to the "tipping" of the equilibrium. This happens, among other things, through putrefaction processes in the sludge. In larger swimming ponds, the sludge layer can become comparatively thick before it has a negative effect on the water quality. Yet
this layer should be removed regularly. In spring this can be easily done with a sludge vacuum cleaner. Automatically working devices can keep the bottom of the swimming pond clean without any effort or effort.Fish species
If fish are to be kept in a swimming pond, there are advantages and disadvantages. The benefits include:
- Fish can reduce algae, plants and aquatic insects
- The pond serves both for swimming and as a biotope
- The pond is built up more naturally and has to do without chemicals
One of the disadvantages is that the fish produce metabolic end products themselves and thus pollute the water. This in turn can increase the concentration of nutrients in the water and thus lead to increased algae growth and tipping of the water. Therefore, on the one hand, the correct fish species and, on the other hand, only a few specimens should be used.
Native bitterling(Rhodeus amarus)
- becomes only up to 10 centimeters long
- feeds on parts of plants and small animals
minnow(Cyprinus phoxinus L.)
- becomes up to 12 centimeters,
- feeds on flying insects and soil animals
Goldfish(Carassius auratus)
- can reach lengths of up to 100 centimeters
- churns up the soil heavily in parts, therefore only suitable to a limited extent
Dogfish(Umbra)
- grows to about 15 centimeters
- is robust and adaptable
Koi(Cyprinus carpio)
- reaches lengths of up to 120 centimeters
- is both sensitive and demanding
- therefore only conditionally suitable for the swimming pond
Rudd(Scardinius erythrophthalmus)
- becomes up to 30 centimeters long
- feeds on plants and small animals
Veil tail(Carassius gibelio forma auratus)
- reaches lengths between 10 and 20 centimeters
- comparatively slow swimmer
Stickleback(Gasterosteidae)
- only up to 10 centimeters long
- shows itself very vividly
Although goldfish and koi are very popular as pond fish, they are not the best choice for the combined ponds. Kois are sensitive and need both special food and very demanding filtering of the water. Goldfish, on the other hand, reproduce quickly, can churn the ground and also produce considerable amounts of feces. With the appropriate precautions, however, they can also be kept in small numbers in the swimming pond.
