crustacean - any mainly aquatic arthropod usually having a segmented body and chitinous exoskeleton

daphnia, water flea - minute freshwater crustacean having a round body enclosed in a transparent shell; moves about like a flea by means of hairy branched antennae

fairy shrimp - small freshwater branchiopod having a transparent body with many appendages; swims on its back

Artemia salina, brine shrimp - common to saline lakes

tadpole shrimp - a kind of branchiopod crustacean