Daphnia
Guides
Cladocera
water fleas
Cladocera is a suborder of small crustaceans commonly known as water fleas, ranging from 0.2–6 mm in size. They are found in freshwater environments worldwide, including rivers, lakes, swamps, and temporary pools, with some species inhabiting brackish water, groundwater, and even leaf axils or caves. These organisms play a central role in freshwater food webs as filter-feeders that consume phytoplankton, bacteria, and organic particles, while serving as essential prey for fish fry and predatory insect larvae. Their sensitivity to environmental changes makes them valuable bioindicators for water quality assessment.