Daphnia is a water flea

Wikipedia: Daphnia

, a genus of small

planktonic

crustaceans

, are 0.2–5 millimetres (0.01–0.20 in) in length.

Daphnia

are members of the

order

Cladocera

, and are one of the several small aquatic crustaceans commonly called

water fleas

because their

saltatory

(

Wiktionary

) swimming style resembles the movements of

fleas

.

Daphnia

live in various aquatic environments ranging from

acidic

swamps

to

freshwater

lakes, ponds, streams and rivers.

The two most readily available species of

Daphnia

are

D. pulex

(small and most common) and

D. magna

(large). They are often associated with a related genus in the order Cladocera:

Moina

, which is in the

Moinidae

family instead of

Daphniidae

and is much smaller than

D. pulex

(approximately half the maximum length).

Daphnia

eggs for sale are generally enclosed in

ephippia

(a thick shell, consisting of two

chitinous

plates, that encloses and protects the winter eggs of a cladoceran).

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