Daphnia Overview: Water Flea In Aquarum


Last updated on June 26th, 2022 at 09:16 pm

Daphnia is a type of plankton that can be found in freshwater environments. They are very small, typically less than one millimeter in size, and are able to move around by swimming or jumping. They eat algae and other tiny organisms, and they play an important role in the food web as a source of food for other aquatic animals. They are also used as a model organism in research studies.

They can be collected by using a plankton net, and they can be kept in a jar of water with some algae for food. They reproduce rapidly, so it is easy to maintain a large population of them. It is an interesting creature to observe under a microscope, as they can be seen swimming around and eating with their mouthparts.

When kept in an aquarium at room temperature, it is able to reproduce even when there is no food present. This means that most of the offspring produced will die due to starvation because there are not enough algae for all of them to eat, but a small number will survive and repopulate the aquarium.

Species profile


The water flea, more formally known as the Daphnia, is a tiny crustacean that can be found in both fresh and saltwater. They are typically less than a centimeter long, but can grow up to twice that size. They are filter feeders, meaning they eat by straining food particles from the water.

They are a keystone species in their ecosystems, meaning they have a significant impact on the health of their surroundings. They play an important role in cycling nutrients and keeping waterways clean. Their populations also provide food for other aquatic organisms, including fish and birds.

What is daphnia?


Daphnia is a genus of small, aquatic crustaceans that live in freshwater habitats all over the world. There are dozens of different species of daphnia, but they all have one thing in common: they’re tiny! Most daphnias measure just a few millimeters in length, making them some of the smallest animals on Earth.

They are small, freshwater crustaceans in the order Cladocera. They play an important role as a food item for young fish in many aquaculture operations and also serve as bio-indicators of water quality.

They are hardy organisms and their populations are largely stable. They do, however, face predation from other organisms such as fish and birds – so their numbers can change based on the presence of these predators in the environment.

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Common name:- Water flea

Daphnia order:- Cladocera

Daphnia kingdom:- Animalia

Daphnia Phylum:- Arthropoda

Daphnia family:- Daphniidae

Appearance and characteristics

They are small, shrimp-like creatures that live in freshwater. They have a transparent body and can be up to 0.75 inches long. They are filter feeders and eat algae and other microscopic organisms. They reproduce rapidly and can produce up to 500 offspring in just two weeks.

They are able to swim backwards and forwards, and can move through water at a rate of one body length every six seconds.

Systematics and evolution

They are in the order Cladocera and the family Daphniidae. There are around 100 species of daphnia, all of which are found in freshwater.

The first daphnia was described by Carl Linnaeus in 1758. He named them Daphnia pulex, or “pale daphnia.”

The cladoceran family Daphniidae is believed to have evolved from the chydorid family around 400 million years ago.

Ecology and behavior

They are planktonic crustaceans that live in freshwater, but also can be found worldwide in brackish water. They are approximately 0.39 inches long and have a transparent body with about 20 segments along their sides terminating with male or female structures on the last segment.

The body of daphnia is also covered with hair-like bristles. They are filter feeders and can consume large amounts of food in a short period of time.

They have two types of swimming: passive and active. Passive swimming occurs when they move because the water moves around them, while active swimming happens when they use their legs to move forward.

Where does daphnia live (Daphnia habitat)?

They live in freshwater habitats all over the world. They can be found in ponds, lakes, and creeks. They are very sensitive to changes in their environment, so they are a good indicator of water quality. If the water is polluted, daphnia will die

What do daphnia eat?

They eat plankton and other small organisms from the water. Since they are so small, they have to filter a lot of water through their mouthparts in order to get enough food. They usually feed on phytoplankton (microscopic plants), but sometimes they will consume zooplankton (microscopic animals).

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They are an important part of the food web. They are eaten by fish, birds, and other aquatic creatures. They also play a role in keeping the water clean by eating pollutants.

Does Daphnia lay eggs?

Yes. They reproduce sexually and a female can produce up to 500 eggs at once. The eggs are deposited on water plants or other surfaces and hatch in about two days. When the young daphnia emerges, they are miniature replicas of their parents.


They have a complex lifecycle that includes a resting stage. The life cycle starts with the female laying eggs, which hatch into tiny larvae called nauplii. Nauplii undergo several molts before becoming adults. Adults can produce more eggs, which start the process over again.

There are usually four to six generations of Daphnia in a year. There are many factors that can affect their life cycles, such as water temperature and food availability. For example, the number of generations is much lower when winter temperatures drop below -15 degrees Celsius.

At this point in time, there may be only one generation per year or even no reproduction at all!

Daphnia reproduction


They reproduce asexually by parthenogenesis, meaning that females produce clones of themselves without mating. The offspring are genetically identical to their mothers. This allows daphnia populations to quickly recover from population losses.

In addition, daphnia can also reproduce sexually by mating. When the female Daphnia is ready to lay eggs, she scoops a depression into the sand or other substrate and deposits her eggs. The male then releases his sperm in order to fertilize them.

The male dies after fertilizing the eggs. The eggs then hatch into miniature daphnia, which grows and reproduce asexually.

Culturing daphnia

Culturing daphnia can be done using a fish tank or aquarium, water from the tap (treated with dechlorinator), gravel/sand, and some plants.

First, you need to clean your container, then add sand as substrate which will serve as their habitat. You should also add an air stone connected to airstone tubing that leads outside of the container (to prevent CO₂ accumulation).

If you would like to keep your daphnia alive for a long time, it is best to use aged water. You can prepare this by leaving tap water in an open container outside overnight and then changing its temperature from day to night over several days. This will allow bacteria that produce C₄H₅O₈ (carbonate) to accumulate, and they will remove CO₂ from the water.

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Next, you can add your daphnia by placing them into a small net bag and lowering it down carefully on the end of a stick. The daphnia should be able to swim out of the bag into your tank, but if they do not seem to be moving try tapping the side of the container gently.

You should also add some snails to eat any algae that form on your plants and gravel/sand, while they are happy eating green water or bits of bread placed in the tank. To get them to reproduce, you can place a small piece of red meat in the tank.

If your container is kept outdoors, make sure to bring it inside during cold weather and add some insulation (e.g. styrofoam) around the sides to help keep the water warm.


They are often infected with parasites, some of which can be deadly. The most common parasites are protozoa, which are single-celled organisms. Other parasites include fungi, bacteria, and viruses. Some of these parasites can also infect humans.

Protista is a large group of parasitic and nonparasitic single-celled organisms. The most common protozoan parasites of Daphnia are the ciliates. These microscopic creatures have hair-like projections called cilia that they use to move around and capture food. Ciliates can cause serious damage to the Daphnia’s cells, leading to death.

Another common parasite of Daphnia is a fungus called Nosema. These fungi can also infect humans, causing diseases such as cryptococcosis and histoplasmosis.

Daphnia is sometimes infected with viruses that cause serious illness in both animals and humans. One example of this type of virus is the Entamoeba invadens trojan (EIT).

What do Daphnia need to survive?


Daphnia needs a habitat that provides the following: food, water, and oxygen in order to survive.

Water must be fresh or brackish (saline). It is recommended for Daphnia keepers to have an air stone with its own power filter in their aquarium because it will provide much-needed aeration. Regardless of whether you have live plants or not, some décor is necessary to provide cover and security for the animals.

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Food can be a challenge because Daphnia is not easy to feed in captivity. They will eat green water (algae), but this can be difficult to maintain. Brine shrimp, mosquito larvae, and plankton are good alternatives.

It is also very important not to overfeed your animals, as this can lead to increased algae growth in the tank and increase the concentration of organic wastes (such as fecal matter).

This combination of elements is ideal for encouraging outbreaks of disease. It’s best practice when keeping Daphnia in captivity to feed them often but sparingly.

Why is daphnia important?

They are important because they are a keystone species in aquatic ecosystems. Their populations play an important role in controlling the abundance of algae and other organisms. They also serve as a food source for many fish, birds, and other animals. As such, their loss could have serious consequences for the health of aquatic ecosystems.

Uses of daphnia

They are used in many different ways:

  1. They are a popular food item for fish, birds, and other animals.
  2. They are also used as a model organism in biomedical research and as a source of protein for human consumption.
  3. Additionally, they can be used to test the toxicity of water and other environmental samples.


Daphnia are small, freshwater crustaceans that play an important role in aquatic ecosystems. Not only do they provide food for many animals and assist with nutrient cycling, but their populations also help keep algae levels under control to maintain the health of the ecosystem as a whole.

Their loss could cause serious problems for other organisms living in affected habitats or even for humans who rely on these ecosystems for their food. For all of these reasons, it is important to protect daphnia populations and keep them healthy.