Daphnia photo and description, development and population

Daphnia (lat. Daphnia) is a plankton, a representative of small crustaceans. It is a small crustacean that lives in fresh water on almost the entire planet. Has a miniature size, is an important chain of the ecological system.

Due to rapid reproduction, daphnia is eaten by many fish and amphibians.

It was discovered in 1785 by Professor Müller.

The detachment consists of 50 species, significantly different from each other. There are two large subspecies Daphnia and Ctenodaphnia.

The ancestors of modern Daphnia appeared more than 150 million years ago, in the Jurassic period. During this time, the crustacean has constantly evolved, constantly adapted to changing conditions, giving rise to new species. The Cretaceous period consolidated the features inherent in modern daphnia.

What does it look like

Daphnia reaches a length of 2 to 5 mm. Such a small size can be studied with a microscope. The body has an oval shape, covered with a chitinous frame that protects the insides. The head has antennae that serve as organs of smell. With their help, the crustacean can repel, swim, jump in the water. Moves with the help of the chest legs.  The female has special bags that provide gill breathing. These bags are covered with bristles, which in turn filters the water. The legs are in constant motion, swinging continuously.

May have different shapes and sizes, it depends on the environmental conditions. The body is covered with a chitinous shell and has transparent valves through which you can see the internal structure. Transparency makes daphnia almost invisible in water. The head was left uncovered, it has two eyes. Sometimes there is a third eye on the head. There are antennae, with their help through the waves, she moves. On the outgrowth, located on the head, there is a pair of antennae that help to move. The body is flattened on the sides. The legs are thickened and underdeveloped, they do not participate in walking. The animal has a complex digestive system, consisting of a complete esophagus, stomach and intestines. Crustaceans have a heart that beats very fast, up to 300 beats per minute.

The respiratory system is located on the body and consists of respiratory appendages located on all limbs.

Where does it live

Found all over the globe. Scientists have discovered some representatives even in Antarctica. This fact indicates how well they adapt to various conditions of life and the possibility of transformation into other species.

Daphnia adapts to a new environment, with each species living in its own habitat.

Some species prefer subtropics and temperate zones for living. The smallest number inhabits the equator and tropical climate. A number of species inhabit America and Great Britain, Europe and Asia. Crustaceans prefer stagnant water, dislike currents. Therefore, a pond or lake, as well as small puddles, is considered a favorite habitat. Mostly inhabits fresh water.

Arthropods, which ended up in droughts, can move to a salty reservoir. The ability to adapt saves their life.

Pure water with minimal soil content is considered the best habitat.

The crustacean feeds on filtering, so the cleanliness of the reservoir comes to the fore.


There are about 100-150 types of crustaceans. In Eurasia, you can find the following: Magn the largest, puns average in size and Moin, the smallest.




Food is always in the stomach of Daphnia. It is ideal as a feed for aquarium fish. It contains the beneficial substances necessary for the power of aquarium inhabitants. Life life of about 3 weeks. Crustaceans inhabit natural reservoirs in a natural environment.

How it eats

Feed on blue-green bacteria and yeast. The largest number of individuals can be found in a reservoir where water blooms and where there are few fish.

Single-celled organisms filter water. Food that has been filtered enters the digestive organ, then moves through the esophagus. With lips, with the help of salivary glands, the crustacean glues food into a lump. It is filtered from 2 to 10 ml per day. In case of cold weather, daphnia can hibernate. Without food, she can hold out for a day, since her stomach always has plant foods. In hungry times, it feeds on the remains of dead plant food and the remains of invertebrates.

How it breeds

They have an amazing ability to reproduce. Daphnia breed offspring without fertilization. The female has a brood chamber on her body. If conditions are favorable, then an adult female lays from 10 to 50 eggs. Then they develop in the brood chamber. Three days later, the breeding cycle is repeated. The water of the reservoir turns red when a huge number of crustaceans teem there. In autumn, the breeding process takes place with the participation of males. With their help, the shell of the eggs becomes the density of the structure and is able to withstand cold. With the onset of warm weather, the breeding cycle repeats.

Daphnia as fish food

Due to its high nutrient content, daphnia is an excellent food for aquarium inhabitants. In artificial conditions, it is quite difficult to breed it, so it is purchased in pet stores in a live, frozen or dried form. In the aquarium, daphnia is an excellent food for medium-sized or young fish. The dried crustacean is completely ready for consumption, frozen daphnia is packed in blisters and sold in pet stores. The use of crustaceans has a great effect on aquarium inhabitants. 50% of the mass of a crustacean consists of a high level of proteins. Its calorie content is similar to bloodworm, gammarus, caddisfly, amphipod, cyclops, pond snail, but daphnia contains a high level of protein.

To breed daphnia in an aquarium, you need the following:

  1. Choose a special glass container that will hold from 1 to 3 liters, wash it thoroughly, do not use abrasive substances.
  2. Water must be purified, free of chlorine and chemical impurities.
  3. The required hardness of water should be from 5 to 17 degrees, pH from 7 to 8.
  4. Aquarium with daphnia should be kept away from direct light. The crustacean does not grow well in strong light. Using a 20 volt fluorescent lamp, you need to provide it with natural light during the day.
  5. The water temperature should be between 20 and 24 degrees. If the water is colder, then it will not be able to reproduce.

Daphnia in the aquarium must be fully fed, dissolve the top dressing in the water until cloudy, then add a new portion.

It is worth carefully cleaning the walls of the aquarium and, if necessary, changing the water. Oxygen must be supplied to the aquarium.

Daphnia is purchased in the form of eggs, then they are launched into a container. When the eggs are ripe, they are caught with a net and used as feed, dried or frozen.

Interesting Facts

  1. Daphnia is called the sea flea.
  2. You can only look at the crustacean carefully with a microscope.
  3. Moves with jerks.
  4. New species constantly appear due to the high adaptability and variability of the species.
  5. The heart muscle contracts at a rate of 200-290 beats per minute.
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