Daphnia can be found in almost any permanent body of water, even in rain-filled tire ruts or several meters from the ground, growing in tree moss in a rainforest. They are mainly freshwater and the highest concentrations of Daphnia populations are found in the vegetation in most lakes and ponds. They are often the most abundant organism in a body of water. They live as plankton in the open water of lakes, or live either attached to vegetation or near the bottom of the body of water.
While very prolific in most freshwater bodies, Daphnia are too small and weak to live in a strong current, which they are unable to swim against. They live in a water column and are light enough to stay suspended by using their legs and antennae for movement. They live mainly in the upper portion of this water column near the algae-rich surface of the water, but they will often move up or down the column depending on seasons or predators in a process called diel vertical migration. They are often forced to expend a large amount of energy moving towards a lower depth during the day in order to avoid predators and coming towards the surface to eat at night. Their location is also controlled by seasonal variation in their phytoplankton food supply.
Aquatic Biomes: benthic ; lakes and ponds; rivers and streams; coastal