Definitions for water flea
Random House Webster's College Dictionary
any tiny freshwater branchiopod crustacean of the order Cladocera, as the daphnia.
Origin of water flea:
cyclops, water flea(noun)
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
daphnia, water flea(noun)
minute freshwater crustacean having a round body enclosed in a transparent shell; moves about like a flea by means of hairy branched antennae
Any of various aquatic crustacea characterised by their jumping or jerky mode of swimming; mostly species of Daphnia.
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