Common name for Daphnia

Wiktionary Word definitions in Wiktionary
n. Any of various aquatic crustacea of the order Cladocera, characterised by their jumping or jerky mode of swimming.

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
Water flea \Wa"ter flea`\ (Zo["o]l.) Any one of numerous species of small aquatic Entomostraca belonging to the genera Cyclops , Daphnia , etc; -- so called because they swim with sudden leaps, or starts.

WordNet Word definitions in WordNet
n. minute free-swimming freshwater copepod having a large median eye and pear-shaped body and long antennae used in swimming; important in some food chains and as intermediate hosts of parasitic worms that affect man e.g. Guinea worms [syn: cyclops ] minute ...