Definition of daphnia in US English:



  • A tiny and semitransparent freshwater crustacean with long antennae and prominent eyes, often used as food for aquarium fish.

    Genus Daphnia, order Cladocera

    Also called water flea
    • ‘The fish are still feeding heavily on the prolific green daphnia.’
    • ‘A large part of their diet consists of many winged insects, a large assortment of aquatic insects, and some zooplankton such as daphnia.’
    • ‘Fish are feeding on small light olive buzzers and daphnia.’
    • ‘In addition to fish, other aquatic creatures such as clams and daphnia are used as indicators of chemical changes.’
    • ‘When they reach a length of 12 mm, chub begin to feed more on small invertebrates, particularly chironomid larvae and tiny crustaceans, such as daphnia.’
    • ‘Small fish begin by feeding upon zooplankton, mainly cladocera, such as daphnia, before moving onto bloodworm and larger invertebrates as they grow.’
    • ‘They are not fighting for breath as some people believe, but are instead feeding on the dense clouds of daphnia that gather just below the surface.’


Modern Latin, from Greek Daphnē, from the name of the nymph Daphne.