Cypris are ostracods (a type of crustacean) and related to mussels and shrimp. They are small, about 1/2 - 2mm long, with a hard outer shell. In freshwater ponds they are usually found scuttling around among the debris at the shallow edges. They swim smoothly with appendages extended from between the two halves of their carapace (shell). When disturbed, they withdraw their limbs into their shell and clamp the halves tightly together.

They can be seen with your lowest power (40x) on a compound microscope. Due to the opaque shell which makes it difficult to see their internal structure, just the antennae and limbs appear out of the gap between the two halves of the shell . Young specimens are the most rewarding for examination, as their shells are generally more transparent than those of the adults.

They are food for the Hydra and small fish.