In winter, when Lake Servières is covered with ice, the fish survive by staying at the bottom of the lake where the density is maximum and water at a constant temperature around 39.1° F (3.98° C). They can keep feeding and breathing as the phytoplankton continues producing oxygen through photosynthesis and the zooplankton and insects still thrive. The fish's metabolism only slows down to adapt to the scarcity of resources.