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 reach a length of about 3 millimeters 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.

Installing 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. 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 more than just setting up a tank. The ecosystem they thrive in includes freshwater plants like duckweed and shrimps 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 be at the top, especially for juveniles and babies.

Keep water temperature at around 68 degrees Fahrenheit (20° Celsius). Additional freshwater plants, such as duckweed, can 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.

Daphnia is killed by chlorine, so make certain you condition your water before using it. 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. Daphnias will be attracted to the light.

Indoor Tank or Outdoor Tank?

Where you physically place your tank is important. Some Daphnia owners keep it outside, but it is best to bring it inside for 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 any problems with Copepods (“Cyclops”) indoors.

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 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 reach a very rapid ‘rolling boil” consistency. The Daphnia are able to swim to calmer water if you place the aeration at the one end of your tank. Standard airline tubing can be used to keep the water moving. Static water is preferable to aeration. This makes sense because, in the wild, Daphnia living in a pond or stream would thrive well in moving water. This really makes your yields increase.

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

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. You should choose ones that don’t prey upon the 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 can add lots of food yeast to your water, as well as spirulina. They will eat plenty! 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 are great at exponential math. A baby Daphnia can grow to maturity in eight days and then start breeding. Each Daphnia has ten babies. A Daphnia can produce 1000 Daphnia within a week if it has 100. In a week, you will have 10,000 Daphnia. And so on! Within a month you can go from 100 Daphnia down to 100,000 Daphnia. Their life cycle is only a couple of months.

#3 – Don’t Underestimate Food Amounts

Your Daphnia population, along with #2 above is on the rise. Do not underestimate how many Daphnias are eating, and how quickly they grow and reproduce. Even when you do daily harvesting, that’s still some serious breeding population numbers to deal with.

– Handling the Daphnia Population Crash

Daphnia breeds so quickly and in such large numbers that you may experience population crashes. This is especially true for smaller tanks. Larger tanks can hold more Daphnia waste, so larger tanks are better. You would probably want at least 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. However, they will be fed active dry yeast in your tank. It is the same stuff that you use to make bread. It is a type if cake yeast that remains semi-dormant. Mix the yeast with some water to activate the cultures. It is possible to mix the ingredients with an immersion blender instead of mixing by hand. Your Daphnia food has now been prepared.

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

How often should Daphnia get fed? This depends on the condition of your tank’s water. Once the water is clear, that’s when it’s time to feed. Sprinkle the yeast mixture onto the surface. At feeding times, the Daphnia becomes very active.

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.

To extract as much water as possible, gently push the strainer against the Daphnia high-density at the surface of the water. These Daphnia will be light brown in color and you’ll see many of them in your net. To get rid of any water remaining in the tank, lift the net gently from the tank. Do not scoop the net more than a few times. Stick to the tank’s surface.

With just a few scoops you can easily get a large amount of Daphnia. They are 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 reproduce quickly. Harvesting is a good way to prevent crashes and make life easier for existing Daphnia.