A class of crustaceans found chiefly in freshwater ponds, lakes, and brackish waters. It includes fairy shrimps (order Anostraca), tadpole shrimps (order Notostraca), water fleas (order Cladocera; see daphnia), and clam shrimps (order Conchostraca). Branchiopods are small (typically 0.25–100 mm long) with fused thorax and abdomen and leaflike appendages used variously for swimming, feeding, or respiration. All except the anostracans have a platelike carapace enclosing some or all of the body.