Daphnia Culture – How to Raise Daphnia

Would you like to grow and raise your own Daphnia (also called water fleas) in your own tank? These plankton-like freshwater crustaceans can grow to a length of about 3 millimeters or less. These adorable little creatures can be seen swimming almost vertically within their tank. They live quite happily in large groups within a tank, so that you can harvest them when you need them to feed your fish, tadpoles, salamanders, newts, or aquatic insects.

We’ll be covering everything you need about the tiny Daphnia to ensure you have a steady, fresh, and successful food supply.

Setting up a Daphnia Tank

Daphnia can be kept in small tanks up to 5-6 gallons. They can also be kept in larger tanks up to 360 gallons. A tank should have a larger surface area than its depth. This allows them to mimic the natural environment of freshwater habitats like ponds. A store sized 360-gallon tank used to cultivate thousands of Daphnia for hundreds of fish measures six feet long, four feet wide, and only two feet tall. You should choose smaller tanks that aren’t as deep.

It’s not just putting together a tank, but an ecosystem for Daphnia. They thrive on freshwater plants such as duckweed, shrimps, or snails, as well algae. Daphnia keep the water clear just as saltwater shrimps. However, when you have many of them, the water can appear much darker than it really is. They far prefer living at the top of the surface of the water, especially the babies and juveniles.

You want water temperatures to be around 68°F (20°C). Freshwater plants like duckweed can be added, too. Wonder Shells can make a huge difference in the level of electrolytes and minerals. It adds hardness to the water and is also a dechlorinator.

Chlorine kills Daphnia, so make sure you properly condition your water first. You should change your water every month. Also, take half of your tank’s water out and replace it with dechlorinated water. You can add fresh fish water from another aquarium or your own pond. Better to have older water.

Daphnia are photosensitive so it helps to have a light on your tank running 24/7. Daphnia will gravitate to light.

Indoor Tank or Outdoor Tank?

It is crucial to choose where you place your tank. While some Daphnia owners keep theirs outdoors, it’s best to bring the tank inside due to the following reasons:

– Temperature indoors: There are less temperature fluctuations. – No mosquito larvae – any mosquito eggs that aren’t eaten by the Daphnia turn into larvae, which turn into mosquitos. You can prevent invasive species by keeping your indoor tank free of Copepods (“Cyclops”) and other species.

Tank Aeration

What about aeration. This is a confusing topic and a very popular one when it comes down to Daphnia. Aeration will give you a higher yield, so it is recommended. Daphnia thrive on a coarse stone like this, which is especially important if it’s not too heavy so that they don’t sink. The medium sized bubbles can be at a pretty rapid ‘rolling boil’ consistency. The Daphnia can swim from one end to the other if they need calmer water. The water will flow through standard airline tubing. Static water is preferable to aeration. This is because Daphnia would thrive in moving water in the wild. This will help you increase your yields.

Another problem that aeration solves is keeping freshwater plants such as duckweed in check. A space can be cleared by constant bubbles.

Shrimp and Snails

Daphnia and duckweed aren’t the only living things to have in your tank. Especially if you have a very large tank with Daphnia, it helps to have more debris feeders like freshwater shrimp and snails. They should not prey on Daphnia. They will clean out the bottoms of the tanks by eating extra yeast or other microscopic particles.

Busting Daphnia Tank Myths!

There are many myths that you may have heard or read about when setting up your Daphnia aquarium. Let’s take a look at each one.

– Green Water Doesn’t Matter

Green water is not necessary. Daphnia can clean large quantities of water in just two days. So, don’t be afraid to add lots of food yeast and spirulina. They will eat a lot! The smaller the tank, the less green water you will see because the Daphnia clean it up so fast.

#2 – Daphnia Reproduce Every 8 Days

Daphnia are really good at exponential math. A baby Daphnia can grow to maturity in eight days and then start breeding. Each Daphnia has ten babies. In a week, 100 Daphnia will give birth to 1000 Daphnia. You’ll have 10,000 Daphnia a week later. Continue this process! Within a month you can go from 100 Daphnia down to 100,000 Daphnia. They live for a few months.

#3 – Don’t Underestimate Food Amounts

Along with #2 above, your Daphnia population is skyrocketing. You shouldn’t underestimate their appetite and the speed at which they reproduce and grow. Even with daily harvesting, you still have a lot of breeding population to handle.

– How to Handle the Daphnia Crash

Daphnia are known for their rapid breeding and large numbers. This could lead to population collapses. This is especially true of smaller tanks. More water can handle more waste from the Daphnia, so bigger tanks are better. A 55-gallon tank is recommended.

What can I feed Daphnia

In their natural pond habitats, Daphnia feed on algae, bacterial flora, and other tiny plankton creatures even smaller than themselves. However, they will be fed active dry yeast in your tank. It is the same stuff that you use to make bread. This yeast is a semi-dormant variety of cake yeast. Mix the yeast with some water to activate the cultures. You might want to use an immersion blender rather than mixing by hand. You are now ready to eat Daphnia foods.

Spirulina powder can be added to your Daphnia aquarium. It’s an algae superfood, which turns the water green.

How often should Daphnia be fed? It all depends on how clean the tank is. When the water is clear it’s ready to be fed. Sprinkle the yeast mixture on the surface. The Daphnia get very active during feeding.

Daphnia can also eat algae. You can grow these green plants alongside your tanks.

How to Harvest Daphnia

It is easy to remove your Daphnia live from your aquarium to feed your fish or other aquatic animals. All you will need is a handled fine mesh aquarium strainer net and a container to put the Daphnia in.

Gently push the strainer under the high-density Daphnia to extract as much water as possible. These Daphnia are a light brown in color, so you will see a lot of them in the bottom of the net. Gently lift the net out of the tank. Then shake it gently to get rid of any water. Only scoop through a few times, and don’t make your movements too fast or ‘swishy.’ That will drudge up the debris from the bottom of the tank. Stick to the surface of the tank.

After just a few spoonfuls, you can get a surprising amount of Daphnia. They are so small. Once you’ve harvested your Daphnia, you can transfer them directly to the fish tank for feeding or put them in a tiny water jar for fish feeding within the hour or so.

Harvest a lot! It won’t kill a population if you harvest as much as possible. They will only reproduce quickly. Actually, harvesting often helps to avoid crashes and makes life easier for the Daphnia.