Daphnia Culturing – 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. You can see them swimming vertically in their tanks, which is quite cute. 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.

In this article, we’ll discuss everything you need to know about these teeny Daphnia, so that you can have a successful, fresh, and continuous 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. You should look for a tank with a larger surface area and less depth. That helps mimic their natural environment of ponds and other freshwater habitats. 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. For smaller tanks, choose ones that aren’t too deep.

It’s much more than creating a tank. The ecosystem they thrive in includes freshwater plants such duckweed, shrimps and snails as well as 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 prefer to live at the top of water, especially for the juveniles and babies.

As for water temperature, you want to keep it around 68 degrees Fahrenheit (20 degrees Celsius). Freshwater plants like duckweed can be added, too. Wonder Shells can make a huge difference in the level of electrolytes and minerals. It increases the hardness of the water and acts as a dechlorinator.

Chlorine kills Daphnia, so make sure you properly condition your water first. At least once per month, change the water and then take out half the tank to get fresh water. You can add fresh fish water from another aquarium or your own pond. Water that has been stored for a while is more beneficial.

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

Indoor Tank or Outdoor Tank?

Where you physically place your tank is important. While some Daphnia owners keep theirs outdoors, it’s best to bring the tank inside due to the following reasons:

– Temperature – there are fewer temperature fluctuations indoors. – No mosquito larvae – any mosquito eggs that aren’t eaten by the Daphnia turn into larvae, which turn into mosquitos. – Prevent invasive species – you won’t have problems with other species like Copepods (“Cyclops”) in an indoor tank.

Tank Aeration

What about aeration? This is a popular and confusing topic when it comes to keeping Daphnia, and there’s a lot of conflicting information. Aeration will give you a higher yield, so it is recommended. Daphnia love a coarse, weighted air stone that doesn’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. Water flow will be maintained by standard airline tubing. It is better to have moving water than stagnant. This makes sense because, in the wild, Daphnia living in a pond or stream would thrive well in moving water. 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. It is a good idea to add freshwater shrimp or snails, especially if you have large tanks with Daphnia. They should not prey on Daphnia. They will clean up the bottom of the tanks, eating extra yeast and 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 are such great water cleaners that they can clean up lots of gallons in a matter of two days. Don’t be afraid of adding lots of food yeast or spirulina. They will eat lots! 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 excel in exponential math. A baby Daphnia can grow to maturity in eight days and then start breeding. Each Daphnia produces ten children. In a week, 100 Daphnia will give birth to 1000 Daphnia. You’ll have 10,000 Daphnia a week later. And so on! In a month, you could go from 100 Daphnia to 100,000 Daphnia. Their life span is just a few months.

#3 – Don’t Underestimate Food Amounts

In addition to #2 above, the Daphnia populations are on the rise. Don’t underestimate the amount of Daphnias they eat and how quickly they reproduce. Even if you harvest daily, there are still serious breeding populations to manage.

– How to Handle the Daphnia Crash

Since Daphnia breed so rapidly and in such large numbers, you could have population crashes. This is particularly true for smaller tanks. A larger tank can handle more Daphnia wastewater, so it is better to have a bigger tank. At most, you would need a 55-gallon tank.

What should I feed Daphnia

Daphnia eat algae, bacterial flora and tiny plankton in their natural pond habitats. You will however feed active dry yeast to them in your tank. It is the same stuff that you use to make bread. This is a semi-dormant type of cake yeast. To activate the cultures, mix the yeast and a little water. An immersion blender may be more convenient than hand mixing. Your Daphnia food is now ready.

Spirulina powder can be added to your Daphnia aquarium. It is an algae superfood that makes the water green.

How often should Daphnia be fed? That depends on the state of the water in your tank. It’s time for you to start feeding once the water has cleared. Sprinkle the yeast mixture onto the surface. The Daphnia become very active at feeding times.

Daphnia will also eat algae, so you can cultivate some of these green plants along the sides of the 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 have a light brown color so there will be a lot in the net. To remove any remaining water, gently lift the net from the tank. Do not scoop the net more than a few times. Stick to the tank’s surface.

A few small scoops can yield a surprising amount Daphnia. They’re so tiny. 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! You won’t decimate a population by harvesting as much as you want. They will only reproduce quickly. Harvesting is a good way to prevent crashes and make life easier for existing Daphnia.