Daphnia Culture – How to Raise Daphnia
What would it be like to have your own Daphnia, also known as water fleas? These plankton-like freshwater snails can grow up to 3 millimeters long. 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.
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 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 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.
You want water temperatures to be around 68°F (20°C). You can also add freshwater plants such as duckweed. 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 are killed by chlorine, so ensure you have your water properly conditioned before adding it to your tank. 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. Aged water is better.
Daphnia are photosensitive so it helps to have a light on your tank running 24/7. Daphnia will gravitate to 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: Indoors, there are fewer temperature variations. – No mosquito larvae. If mosquito eggs aren’t eaten, larvae turn into mosquito larvae. You can prevent invasive species by keeping your indoor tank free of Copepods (“Cyclops”) and other species.
What about aeration. This is a confusing topic and a very popular one when it comes down to Daphnia. 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. 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. Standard airline tubing will help keep the water flowing. 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 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
Daphnia and duckweed aren’t the only living things to have in your tank. Especially if you have a very large tank with Daphnia, it helps to have more debris feeders like freshwater shrimp and snails. Buy ones that won’t prey on 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 take a look at each one.
– Green Water Doesn’t matter
Daphnia doesn’t require green water. 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! 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 at exponential math. A baby Daphnia can grow to maturity in eight days and then start breeding. Each Daphnia can have ten children. If you have 100 Daphnia today, you’ll have 1000 Daphnia in a week. A week after that, you’ll 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 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 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 especially true of smaller tanks. A larger tank can handle more Daphnia wastewater, so it is better to have a bigger tank. A 55-gallon tank is recommended.
What can 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. 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. You might want to use an immersion blender rather than mixing by hand. 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 get fed? This depends on the condition of your tank’s water. It’s time for you to start feeding once the water has cleared. Sprinkle the yeast mixture over the surface. The Daphnia get very active during feeding.
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 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. Gently lift the net out of the tank. Then shake it gently to get rid of any water. Do not scoop the net more than a few times. Stick to the surface of the tank.
A few small scoops can yield a surprising amount 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! Harvesting too much won’t cause a population to die. They will reproduce quickly. Actually, harvesting often helps to avoid crashes and makes life easier for the Daphnia.