Lake Kulundinskoye (Kulunda) has been experiencing a downward trend in water salinity over the past three years (from 2017 to 2020) due to an increase in the overall level of moisture in the Altai Territory. In connection with this decrease, the authors observe changes in the composition of the zooplankton in the hypersaline water reservoir. The biota is replenished with brackish-water hydrobionts and the density of various aged individuals of Artemia crustacean and its cysts decreases under conditions of low water salinity.