The terms “micro” and “crustacean” represent extremely small free-living crustaceans.
Daphnia is a genus of crustaceans of the order Cladocera, commonly called a water flea that is classified as a micro crustacean because of its very small size. Due to the way it is boosted by two antennas located at the top of its head (second antenna), daphnia seems to jump into water as land fleas jump.
However, Daphnia can also be considered a macroorganism, because even very small can be seen with the naked eye and macroorganisms are beings that can be seen with the naked eye.