THE XERCES SOCIETY FOR INVERTEBRATE CONSERVATION

Aquatic Invertebrates in Pacific Northwest Freshwater Wetlands
An Identification Guide and Educational Resource

Water fleas primarily live in still waters, and are dominant in the plankton found in freshwater habitats. Cladocerans are small and generally have a distinct head while the carapace extends over the thorax and abdomen.

While cladocerans are primarily benthic, their antennae are well developed and used as the primary swimming structures. Most eat algae, bacteria, debris, and microorganisms. However four families are comprised of predators of zooplankton.

Filter-feeding cladocerans are among a few known animals that can clear pollution-caused algal blooms in lakes. Moreover, water fleas are a critical part of freshwater ecosystems as most freshwater fish species and many bird species depend on water fleas as a significant source of food.