Water fleas, everything you need to know!

Breeding water fleas is very simple and recommended for anyone with an aquarium. There are also good reasons for this. For example, they are healthy food for your fish, and floating algae that make your water green are a thing of the past. This applies to both your aquarium and your pond. In other words, grow with that bite.

Daphnia are a great food source for aquarium fish. I also use tablets that contain water fleas. I then stick it against the aquarium window. And then watch the fish feast and get good nutrition at the same time.

Breeding water fleas

Breeding water fleas is less difficult than you may think. To make it even easier, first follow the supplies and then a manual. Towards free and good food, that should appeal to the average Dutch person.

Breeding water fleas mainly refers to the breeding of the so-called Dapnia. Actually a kind of small crayfish. The point with the term water fleas is that it’s more of a collective term, a container term, of crustacean organisms that are the same size. This article therefore discusses the animal that everyone actually means by the term water fleas. The Dapnia or the Daphnia pulex.

Anyway, we are going to breed water fleas, what you need for that is quite easy.

A transparent unit that can hold quite a bit of water Nutrients such as flakes, yeast and milk
Tap water or rainwater A landing net, just to keep the end goal in mind
Water snails are very welcome against algae growth on glass windows A screen or gauze so that mosquitoes can’t lay eggs in it


Fun fact : Daphnia (Dapnia) have 31,000 genes. By comparison, you have ‘only’ 23,000. Not bad for such a small water creature.

Step-by-step plan for breeding water fleas

  1. Arrange an old aquarium or a large glass vase.
  2. Place it in front of a window with direct sunlight, but make sure that the water does not get warmer than 28-29 degrees. The water fleas no longer grow above that. Sunlight causes an explosion of algae growth, and we must have that because this is food for the daphnia. You can also simply put a large container outside.
  3. Fill the old aquarium with tap water. The advantage of this water is that there are no annoying other parasites in it. Rainwater is its composition even better.
  4. Leave the container for two weeks and add a splash of milk. Add some flake food after a week. Evaporated water can be supplemented with tap water.
  5. After two weeks, the water will start to turn green. Perfect, that’s what we’re looking for.
  6. Buy a good bag of daphnia from the pet store and release it in the container of green water.
  7. The daphnia will multiply rapidly until the water is clear again. When that moment has arrived, add another splash of milk, some yeast or flake food.
  8. Voila, you have a continuous supply of fish food. Your fish will thank you for the delicious fresh delicacy.

What should you watch out for with water fleas?

Like so much in life, it is possible that on the path to a successful end goal there will be problems or deviations along the way. But that was not said in advance. And there you are with your problems. To help you on your way, some of the most common problems are highlighted below. And more importantly, how to solve or better, prevent these problems.

Problem 1: You have fish in your aquarium

They eat entire water flea populations. In other words, keep the water fleas separate.

Problem 2: the windows are covered with algae

That is a problem because direct sunlight in the tank is important to grow the good algae. Namely the green water floating algae. More information about this alga can be found in the blog about green water floating alga . The solution is simply cleaning or throwing in slugs that can eat the walls clean. Cleaning yourself is a lot faster.

Problem 3: Mosquitoes or polluted water put scum in your water that eat the daphnia

The rule here is prevention is better than cure. The point is that you do not see the rig properly and it is difficult to get it out of the box. Covering the aquarium with an insect screen is a good way to prevent mosquito larvae from ending up in the water.

Problem 4: the wrong algae is created in the tank

Yes that is a problem. Blue-green algae is such an algae that arises spontaneously in the tank. As soon as you see that, don’t hesitate and get this algae out right away.

Problem 5: lack of oxygen

Oxygen aquarium plants in a breeding tank for water fleas is simply not practical. If the water does not move then there is the possibility of oxygen deficiency. An air filter solves this problem with ease.

Problem 6: too hot water

You think, I put my tank in front of a window so that a lot of direct sunlight comes in. Good idea, only daphnia no longer grow in a tank that is warmer than 28-29 degrees. A south-facing window may therefore be too much to ask for. Moving to a place where the sun is not up all day solves this problem immediately.

Fun fact: what you actually want is to promote algae growth in the water flea breeding tank. That is the food for these water fleas. Everything that is not allowed in your aquarium, such as too much food or direct sunlight, is now allowed. Grab your chance and have fun!

Understanding water fleas

Daphnia are an important part of the ecosystem. They have great ecological significance. For the water flea nerds among us, here’s more information about water fleas.

The daphnia can move quickly by means of short shocks. This makes the daphnia particularly fast in the water. Quite handy if you are considered a tasty snack by a lot of animals around you. One way to survive is the ability of daphnia to reproduce asexually. In other words, females can reproduce without males. Only when conditions become unfavorable, the males are created water fleas.

The reason why daphnia are so important in nature is mainly because they are a rich food source for fish, but also salamanders and other insects such as dragonfly larvae. Daphnia are the grass of the meadow or the shrimp of the sea.

However, water fleas have an important other function. They keep water clear, preventing massive algae growth. Without water fleas, many seas would be green instead of blue.

Fun fact: Daphnia are real indicators of water. When there is a lack of oxygen in the water, the water fleas turn red. Colorless water fleas are an indication of water with sufficient oxygen.


Do you have an old aquarium left and do you care a lot about your aquarium fish? Then follow the daphnia breeding guide in this blog and get started today. Do you want to become even more popular with your aquarium fish? Then read the blog with general information about aquarium plants. Your aquarium fish will be grateful for it!

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