The weather reports are forecasting sub-zero temperatures and heavy snowfalls for large parts of Europe. In our last post ( These steps in autumn will make your garden pond fit for the winter. ) we dealt with the steps you need to take before the winter. It’s time for some tips to get your fish unscathed through the long frosts. Even when many processes and activities inside and around the pond are dormant, you still need to pay attention to certain points.
If your pond has a depth of less than 150 cm, it can freeze completely. The thick ice layer will then inhibit the exchange of gases. If this is the case, you will need an ice preventer (e.g. made of styrofoam) which is aerated from below with an additional membrane pump (e.g.: JBL PondOxi-Set ). The surface movement will almost always prevent the water surface from freezing completely. In addition ensure there is a sufficient oxygen supply, for this is essential for your fish.
WARNING: It is still, unfortunately, common practice to break the ice. Please do not. The blast waves are passed on to the fish in a vastly intensified form, causing them enormous stress.
Especially in the deeper zones of the pond the oxygen content can drop rapidly. For this we recommend JBL OxyPond , which can be dosed through the gap in the ice.
If you are still running your technical pond equipment, such as filters, UV-C and similar devices, these need to be uninstalled immediately since the frost can damage the plastic material. If you have a pump under water to ensure water movement, do not position it right at the bottom of the pond. This would result in all the water layers mixing and prevent the 4° water zone from forming above the bottom of the pond, which is where the fish “hibernate” without the need for vigorous movement.
During warmer winter spells fish can sometimes become temporarily active. Make the most of this opportunity and feed them special winter food ( JBL PondEnergil / JBL Koi Energil midi ). It is easy to digest and gives your fish a new burst of life. This way your fish remain resilient and have the energy to get through a long winter.