Daphnia Culturing – How to Raise Daphnia

How would you like to cultivate and raise your own separate tank of Daphnia (also known as water fleas)? These tiny plankton-like freshwater crustaceans grow to about 3 millimeters in length or less. They’re actually kind of cute looking as you watch them swim almost vertically in 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.

This article will cover everything you need to know regarding these tiny Daphnia so you can have a continuous, fresh and profitable food supply.

Establishing a Daphnia Tank

Daphnia are freshwater creatures that can be kept in a tank as small as 5 or 6 gallons and all the way up to 360 gallons! The main thing to look for in a tank is a greater surface area than 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. So, for smaller tanks, find ones that aren’t very deep.

It’s not just putting together a tank, but an ecosystem for Daphnia. Freshwater plants like duckweed, shrimps or snails, and algae help them thrive. 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.

As for water temperature, you want to keep it around 68 degrees Fahrenheit (20 degrees Celsius). Also, freshwater plants like duckweed may be added. 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.

Daphnia can be killed by chlorine, so make sure to properly condition your water. 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. Better to have older water.

Daphnia can be photosensitive so make sure you have a constant light source in your tank. The Daphnia will be drawn to the light.

Indoor Tank or Outdoor Tank?

It is very important to place the tank in a suitable location. Although some Daphnia owners prefer to keep their tank outdoors, it is better to bring it inside.

– Temperature: Indoors, there are fewer temperature variations. – No mosquito larvae. If mosquito eggs aren’t eaten, larvae turn into mosquito larvae. – Avoid invasive species – Indoor tanks won’t cause problems with Copepods (“Cyclops”)

Tank Aeration

What about aeration? It is confusing and popular topic in Daphnia keeping. There are many conflicting information. It is recommended to aerate your plants for a higher yield. Daphnia thrive on a coarse stone like this, which is especially important if it’s not too heavy so that they don’t sink. Medium-sized bubbles can have a rapid rolling boil consistency. If the tank is positioned at one end, the Daphnia will be able to swim to the opposite end for calmer water. Water flow will be maintained by standard airline tubing. Aeration is much preferred over stagnant water. This is because Daphnia would thrive in moving water in the wild. This will help you increase your yields.

Aeration also solves another issue – keeping freshwater plants like duckweed from taking over. The constant bubbles can clear a space.

Shrimp and Snails

Your tank should not be limited to duckweed or Daphnia. It is a good idea to add freshwater shrimp or snails, especially if you have large tanks with Daphnia. You should choose ones that don’t prey upon the 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 look at them one-by-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. 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 excel at exponential math. It only takes eight days for a baby Daphnia to grow to maturity and begin breeding. Each Daphnia produces ten children. You can have 1000 Daphnia if you have 100 Daphnia. A week after that, you’ll have 10,000 Daphnia. And so on! You could easily go from 100 Daphnia up to 100,000 Daphnia in a single month. Their life cycle is only a couple of months.

#3 – Don’t Underestimate Food Amounts

Your Daphnia population, along with #2, is on the rise. So, don’t underestimate how much they’re eating and how fast they grow and reproduce. Even if you harvest daily, there are still serious breeding populations to manage.

– Handling Daphnia Population Crisis

Daphnia are known for their rapid breeding and large numbers. This could lead to population collapses. This is especially 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 do I Feed Daphnia?

In their natural pond habitats, Daphnia feed on algae, bacterial flora, and other tiny plankton creatures even smaller than themselves. In your tank, though, you will feed them active dry yeast. Yes, this is the same stuff used to make bread! It is a type of cake yeast that is still in a semi-dormant state. Combine the yeast with a bit of 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 super food that turns the water green, too.

How often should Daphnia get 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 over the surface. The Daphnia are very active during feeding times.

Daphnia also likes algae so grow some green plants around 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 scoop the strainer through the high-density Daphnia at the water surface to get as much as you can. 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. Keep your eyes on the tank’s surface.

A few small scoops can yield a surprising amount 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! Harvesting too much won’t cause a population to die. They will just reproduce rapidly. Actually, harvesting often helps to avoid crashes and makes life easier for the Daphnia.