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 snails can grow up to 3 millimeters long. 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.

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 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. 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. Freshwater plants like duckweed, shrimps or snails, and algae help them thrive. Daphnia can also help keep water clear, much like saltwater shrimp. However, if there are thousands of them, it can make water appear cloudier than it 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). Also, freshwater plants like duckweed may be added. 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.

Daphnia can be killed by chlorine, so make sure to properly condition your water. Change the water at least once a month and take half of the water out of your tank and replace it with fresh water that’s been dechlorinated. 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 are attracted 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 – 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. You will get a better yield if you air it. 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. Aeration is much preferred over stagnant water. This is because Daphnia would thrive in moving water in the wild. It will 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 take a look at each one.

– Green Water Doesn’t matter

Green water is not necessary. Daphnia have a remarkable ability to clean water. They can clean up large amounts of water in as little as two days. You shouldn’t be afraid adding lots of food yeast and/or spirulina. They will eat lots! You will see less green water if your tank is smaller because Daphnia can quickly clean it up.

#2 – Daphnia Reproduce Every 8 Days

Daphnia are really good at exponential math. It only takes eight days for a baby Daphnia to grow to maturity and begin breeding. Each Daphnia can have ten children. You can have 1000 Daphnia if you have 100 Daphnia. In a week, you will have 10,000 Daphnia. Continue this process! In a month, you could go from 100 Daphnia 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, 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.

– How to Handle the Daphnia Crash

Daphnia are known for their rapid breeding and large numbers. This could lead to population collapses. 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 live in natural pond environments, where they eat algae, bacterial flora, as well as tiny plankton species. You will however feed active dry yeast to them in your tank. Yes, this is the same stuff used to make 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’s an algae super food that turns the water green, too.

How often should you feed Daphnia? That depends on the state of the water in your tank. When the water is clear it’s ready to be fed. Sprinkle the yeast mixture onto 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 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 tank’s surface.

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. In fact, harvesting frequently helps prevent crashes and makes life better for the existing Daphnia.