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. 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.

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

Set up a Daphnia Tank

Daphnia, a freshwater creature, can be kept in tanks as small as 5 to 6 gallons or as large as 360 gallons. A tank should have a larger surface area than its 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 not just putting together a tank, but an ecosystem for Daphnia. Freshwater plants like duckweed, shrimps or snails, and algae help them thrive. Daphnia also keep the water clean, just like saltwater shrimp, although if you have thousands of Daphnia, they can make the water look much cloudier than it actually is. They prefer to live on the top of the water, particularly the babies and the juveniles.

You want water temperatures to be around 68°F (20°C). Also, freshwater plants like duckweed may be added. A Wonder Shell is a great way to increase the electrolyte and mineral content. 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. Aged water is better.

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?

Where you physically place your tank is important. 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 – 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 popular and confusing topic when it comes to keeping Daphnia, and there’s a lot of conflicting information. You will get a better yield if you air it. Daphnia love a coarse, weighted air stone that doesn’t sink. The medium sized bubbles can be at a pretty 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. 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. Constant bubbles can clear out a space.

Shrimp and Snails

Your tank should not be limited to duckweed or Daphnia. If you have a large tank of Daphnia, adding more debris feeders such as freshwater shrimps and snails can be beneficial. 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 go through them one by one:

– Green Water Doesn’t matter

You don’t need green water or to start with green water for Daphnia. Daphnia are such great water cleaners that they can clean up lots of gallons in a matter of two days. You shouldn’t be afraid adding lots of food yeast and/or spirulina. They will eat a lot! Because the Daphnia are quick to clean up the water, the smaller the tank the more green water you will see.

#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. If you have 100 Daphnia today, you’ll have 1000 Daphnia in a week. In a week, you will have 10,000 Daphnia. You can go on and 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 with daily harvesting, you still have a lot of breeding population to handle.

– 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. You would probably want at least a 55-gallon tank.

What should I feed Daphnia

Daphnia eat algae, bacterial flora and tiny plankton in their natural pond habitats. However, they will be fed active dry yeast in your tank. This is the same yeast that makes bread. This is a semi-dormant type of cake yeast. Combine the yeast with a bit of water to activate the cultures. An immersion blender may be more convenient than hand mixing. Now your Daphnia food can be prepared.

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

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 on the surface. The Daphnia become very active at feeding times.

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 scoop the strainer through the high-density Daphnia at the water surface to get as much as you can. These Daphnia are light brown and will often be found in the net’s bottom. To remove any remaining water, gently lift the net from the tank. Be gentle and only scoop through the water a few more times. 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! You won’t decimate a population by harvesting as much as you want. They will only reproduce quickly. Actually, harvesting often helps to avoid crashes and makes life easier for the Daphnia.