Breeding of KOI carp during the winter period.
Preparation for winter.
With the onset of freezing we switch off the pump, drain off the filter, take out the UV-emitter KOI carps during the winter period and drain off all parts of the system which could be damaged by freezing water. We can provide the fish with water aeration if temperature still ranges in 5-8°C but we shall keep in mind that the supply of air chills the water. If the water temperature drops below 3°C it may have unfavourable effect to the KOI carps themselves. If snow falls we sweep it away. It has a simple reason: walls of the reservoir are grown with algae which consume oxygen (dissimilate) if light is lacking while they create oxygen (assimilate) if they have light enough. Oxygenated water is the basic survival condition for the fish! If we dig a little hole into the ice, we can check the fish. They should „sit“ near the bottom and stay in a „shoal“. If they lay on flank, there is something wrong and we have to interfere.
When the weather warms up and spring comes, we clean the filter, rinse it with water but do not add any dissinfection which would kill the desirable filter bacteria. We remove sediments from the reservoir, open valves, switch on the pump and set the whole system in operation. We can also start with supplemental feeding.