How to Raise Daphnia & Care guide

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Daphnias are small aquatic crustaceans, also known as the water fleas; the latter is because of its swimming style as it closely matches that of the fleas.

Daphnias are mostly adopted as food for the aquatic animals, they inhabit the freshwater lakes and ponds or the acidic swamps. 

By including daphnia in the aquarium they tend to activate a fish’s hunting instinct; daphnias reproduce very fast, so there are chances that their population might increase just as fast in the aquarium. This should not worry you a tad though because unlike the other fish food that disintegrates and may cause the production of harmful bacteria. 

Daphnias will live to be eaten later by the fish, we will, therefore, provide you with guidelines on how best to raise the Daphnia as a food source for your fish. 

How to Raise Daphnias

So as we aim to provide our pet fish with an all-natural occurring source of food, it is best that we do it right. Containers used for raising the Daphnia vary as some people use glass jars, and others use aquariums. 

In our case, however, we will be using the aquarium and we will thus need standard airline tubing, an aquarium, an air or bubble stone, dechlorinated water and Daphnia spp.  

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Setting up water in the Aquarium

When it comes to incorporating water in the aquarium you have a variety of options for one you could fill it with dechlorinated water, or rather you could just put in tap water and let it stand for a couple of days. Other options include the use of pond water but this may have illumination issues that will prevent you from having a proper view of what is happening inside the tank, and don’t forget to set up the aerator system. 

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Introducing Daphnia

Don’t just shove daphnia into the aquarium when you want to introduce them to their new environment. As a rule of thumb, you will put them in their new container while still in the packaging that they came with, to help them get acclimatized with the new water temperatures in the aquarium. 

After 15 minutes of acclimatization, they can then be released to swim freely in their new environment. Daphnia reproduces very fast and so at least once every month you should change the water not all of it but half. You will then replace the removed water with dechlorinated water. 

And as you do this, it is very likely that you will carry some of the daphnia’s with you but this should not be a worry because depopulating them isn’t a bad idea. Since we have put all our eggs in one basket, you never know when disaster will strike and leave you daphnia less. So for plan B, separate a few daphnias from the original aquarium with a quart jar. 

Feeding the Daphnia’s

Daphnia can be fed any type of organic matter as long as it is in suspension since the water that the daphnia are contained in is allowed to stand, you could add a piece of lettuce, and let it get soaked and dissolve slowly such that by the end of the week you have a nice green color suspension complete with organic particles for the daphnia to feed on. 

You could also sprinkle some dry yeast on the surface of the water, and let it dissolve and diffuse to reach your tank dwellers. Did you know that you could offer the little sea creatures a treat, well just mix a one-part fish food with two parts water and refrigerate? For a 10 gallon aquarium, you can then pour up to 3 tablespoons of the milkshake that you prepared earlier into the water for your daphnia. 

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Spirulina powder can also be added in the aquarium this will turn the water green but it is a good source of food for the algae, remember that daphnia’s feed on algae so this will help generate them. 

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What time should you feed your daphnia?

Unlike other aquatic animals, daphnia food seems to be ever present in the aquarium thus can be confusing on the appropriate time for adding extra food. Now the state of the water in the tank is a large determinant of when you should feed your daphnia, if the water is still cloudy then you know that food is still in stock. When the water becomes clear you can now feed them, and to know that they were hungry, you will notice that they become super active when you introduce food into the tank. 

How to harvest daphnia

Harvesting daphnia is the easiest process during cultivation as you prepare to feed them to your aquatic animals. So what you will need for the harvesting is a simple handheld aquarium strainer net and a separate container to put in the daphnia. 

By now the population of the daphnia must have exploded in the aquarium so you will have to gently insert the strainer into the aquarium and slowly scoop around the water surface as many daphnias as you can possibly scoop. The reason for the slow careful movements is to avoid messing up with the debris that is settled at the bottom of the tank. 

Feed them to the fish 

The ready daphnia normally features a light brown color, lift the strainer off from the water and shake off the excess water; you can then transfer the contents to the waiting jar or take them directly to the aquarium. Alternatively, you can put them in a tiny water jar, then insert the jar into the fish aquarium so that they can feed within the hour. 

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There is no limit to the amount of daphnia that you can harvest and it will certainly not affect their population. Instead, it will decongest the tank giving them more space to reproduce, removing some of the daphnias will also help prevent crashes. 


Don’t forget to aerate your daphnia aquarium because for one it will prevent the growth of freshwater plants like the duckweed, and will encourage a higher yield.