Daphnia pulex is the most common species of water flea. These crustaceans, a type of water flea, are members of the Class Branchiopoda. Daphnia longispina is a planktonic crustacean of the family Daphniidae, a cladoceran freshwater water flea. The spiny water flea preys on smaller planktonic organisms. The water flea "Daphnia pulex" alternates between sexual and parthenogenetic reproduction. "D. magna" is a typical water flea of the genus "Daphnia".