Daphnia Daphnia species Phylum: Arthropoda Class: Crustacea Order: Cladocera   Daphnia are often called water fleas but they are not really fleas at all ! They are crustaceans, and are covered with a very thin shell. They are found in huge numbers in the lakes, and are a valuable food supply for many creatures.
	Moving around	Daphnia have 2 pairs of antennae. The first are small, whereas the second are large and bristled and used for swimming.
	Feeding	They eat: small green algae. Daphnia are herbivores (primary consumers). The little animals wave their legs, which produces a current of water. The legs filter out tiny algae, and pass them up to the mouth. Edible particles are then ground up by tiny jaws, and pushed into the mouth. They are eaten by: carnivores such as water mites and phantom midge larvae.
	Reproduction   When summer is over, some of the eggs develop into the small males. These can fertilise the eggs in females, which grow into 'winter eggs'. These fertilised eggs can also be found in stressed Daphnia, such as those found in a pond that is drying out.	In the summer, female Daphnia produce eggs, without being fertilised by males. This is called parthenogenesis. Daphnia give birth to live young, but the eggs are first incubated in a brood pouch. This is where the baby Daphnia grow. Look at this Daphnia giving birth !
	Breathing	Daphnia are so tiny, and their outer shell is so thin, that they can absorb dissolved oxygen from the surrounding water. Daphnia contain haemoglobin - which is also found in human blood. This substance can hold and process a lot of oxygen. It turns red when it contains oxygen.
	Size	1 mm
	Fun Fact	Males are uncommon and considerably smaller than the females, which can be easily identified by the presence of eggs in the brood pouch.