Wondersurf 
Winter mode in the garden!
Freezing temperatures and snow!
The lake is frozen
Fish adjust their circulation to the water temperature.
In summer, the water is around 20 °C warm. Then fish are in top form. They swim around actively, eat and gain weight.
In winter, when the water temperature is around 4°C, they swim leisurely in the lower water layers and consume very little food. Some fish fall into a kind of hibernation.