It belongs to arthropods (crustacea, branchiopoda). Small size, about 2MM-3MM long, light flesh red, living in fresh water. The body is divided into a head and a trunk with a carapace. The trunk has five pairs of trunk limbs (chest limbs), which are the organs of movement and breathing.
Daphnia refers to two kinds of zooplankton: aquatic cladocera and cladocera, which are nutritious and easy to digest, and are palatable bait for fry and fingerling.