While there was still wonderful autumn weather in the last few weeks, winter has now arrived. In some regions there was already snow and the temperatures dropped below 0 degrees. If you haven’t winterized the pond yet, it is high time for you. It is important to make some preparations so that the koi can survive the winter unscathed.
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Even if the Koi can survive low temperatures without any problems, the temperature fluctuations are problematic for the animals. Kois are cold-blooded animals, i.e. their body temperature is influenced by the ambient temperature. As the temperatures get colder, the metabolism of the fish also slows down. If the temperatures then rise again, they become more active again. Therefore, the fish should be kept in view so that they do not suffer any damage to their health.
Tensioning of leaf protection nets
Preparations for winter begin as soon as the autumn leaves change color. So that the leaves do not bring too many organic substances into the pond, a leaf protection net should be stretched over the pond. This catches the leaves and prevents them from sinking to the pond floor and rotting there. If you don’t have that many leaves, a skimmer is enough to remove leaves and other dirt particles from the water. At the same time, it is advisable to remove sludge, leaves and plant residues from the pond floor using a sludge vacuum cleaner. This is a gentle cleaning that does not stress the koi.
Water values always in view
Even if the pond is dormant in winter, the water values should still be kept in view. Only good water values guarantee that the koi will get through the winter well and will not be harmed. Metabolic processes are still taking place, even if they are slowed down. There are also entries from outside, such as rain or snow. This causes the water values to change constantly. The values should therefore be checked once a week. This can be done quickly with water tests. The pH value should be between 7 and 8.5, the GH value between 8 and 12, the nitrate value at 0.5 mg / liter and the nitrite value at 0.15 mg / liter. The ammonia value should also not exceed 0.15 mg / liter. Deviations can be corrected directly using the appropriate water treatment agent.
Heat the pond or not?
What is the best way to get the koi over the winter, you might ask yourself. The comfortable temperature for koi is between 15 and 25 degrees, but they can also spend the winter in the pond. There are two possibilities. On the one hand, they can let nature take its course. For this, the pond must be at least 1.50 meters deep. Then the fish with the colder temperatures retreat to the bottom of the pond and hibernate there. Then you just have to make sure that the pond doesn’t freeze over. There are ice preventers for this -> Guide: Ice preventers against a closed ice cover. Over the winter, these ensure that gas exchange takes place between the water and the environment even when the ice cover is frozen. However, there is also the option of keeping the temperature constant at 6 degrees Celsius using a pond heater. Then the animals remain active and can be fed all winter. If the outside temperature fluctuates strongly, you should consider whether pond heating is not the best method for the fish. Excessive fluctuations are too much stress for the animals. Another insulation, such as with PE balls, supports the winter. The PE balls prevent the pond from freezing over and prevent it from cooling too much. Since the balls are transparent, they let enough sunlight into the pond.
Pond technology in winter
Whether the fish overwinter on the bottom or in a heated pond also has an impact on the pond technology. When the fish hibernate, the pond filter and pump also take a winter break. They should be cleaned and maintained with clear tap water and then kept dry in the basement or garage. However, if the pond is heated and the fish are still active, the pond filter and the pump should also continue to operate. Even at the low temperatures, the bacteria work in the filter and break down the pollutants. Going through the pond technique is absolutely recommended. So that these are not affected too much by the temperature fluctuations, it is advisable to insulate them with bubble wrap. Styrodur panels are also well suited for insulation.
The entire winter measures remain in place as long as the temperatures are not constantly above 15 degrees Celsius. And even if the sun rises strongly during the day, temperatures can still drop below 10 degrees at night. Therefore, the winter protection should be left for longer than removed too early.