This article will show you how to culture daphnias at home.
The daphnia is a genus within the order of Cladocera, consisting of small crustaceans also known as water fleas. The daphnias genus represents over 200 species, which can be used to feed fish and fry.
The Daphnia pulex and Daphnias magmas are generally widely available and can be purchased either locally or onliane.
How you house your daphnias will depend on your purpose. The more fish you have and the more you intend to feed them daphnias will determine the size of the tank you need.
For most, 5 to 10 gallons will do.
If you intend to commit to the culture of daphnias on a long-term basis, then you’d want to an aquarium or a container with a capacity of at least 5 gallons. Some even go further and set up 100+ gallon tanks.
It is possible to create a culture in a jar or a small container. Larger setups will provide more stability and can be sustained for longer periods of time. A small setup can easily go wrong due to issues with water quality and temperature control.
You will also need to have a light and an air pump. However, you should avoid using an air stone, as the bubbles they produce are too small, and can enter the carapace of the daphnia. If air enters their carapace, the daphnia will float and will not be able to swim freely, and then die.
Daphnias are my favorite live food to feed my fish. Compared to other live foods, daphnias provide a good food source to a range of fish sizes. Baby daphnias can be fed to most fry since the are small enough to fit into their mouth. If you’re fish fry to small to eat daphnias, you can create an infusoria culture. This can be helpful in the first few weeks of the fry, after which you can feed them daphnias.
Daphnias can be quite sensitive to chlorine, chloramines, and certain metals found in water. When you perform a water change, it’s preferable that you use aged water.
The water aging process is easy. Simply fill a bucket with water from the tap. Place the bucket aside for at least a few days. During this time, harmful chemicals like chlorine and chloramine will evaporate from the bucket. To quicken the process, add a de-chlorinator. Personally, I like to add a de-chlorinator and wait 2-3 days.
How to Setup your Daphnia Tank
This is my take on how to setup a daphnia culture.
I maintain my culture on a long-term basis. I am quite fond of my daphnias. Even though they’re meant to be food for fish, I find it’s important to give them a healthy environment, just as I would with any of my fish.
The idea of maintaining a culture for long periods of time, while being able to feed my fish with fresh live food, is quite a rewarding experience.
This is why you’ll find a variety of plants in my daphnia tank.
I always have daphnias to feed my fish.
A colony can crash due to overpopulation. As the aquarium becomes overpopulated, the water conditions in the aquarium deteriorate. Daphnias begin to die, further deteriorating the quality of water.
To avoid this snowball effect, it is recommended that you perform a 25% water change with a aquarium vaccum. This inevatabiliy will get rid of a least a quarter of your population. This will sustain the lifecycle of your daphnias and avoid overpopulation. Avoid removing more than 50% of your colony population during a single water change.
If you notice your colony’s population beginning to decrease, it’s perhaps best to stop feeding them to your fish. Since daphnias reproduce so quickly, this takes about a week or two.
I prefer to start a culture in an aged setup. A few weeks before I expect my culture to arrive, I’ll set up a tank.
- An aquarium or a container, that holds at least 5 gallons of water.
- Add a thin layer of an inert substrate.
- Add a few stem plant trimmings from other aquariums. Stem plants are a good choice since they can absorb nutrients from the water column and don’t rely on soil like other plants.
- Floating plants. Floatings plants help you maintain optimal water conditions. A good choice is Silvania, which can quickly remove ammonia from the water.
- Fertilizer (optional) – Daphnia’s love to eat algae. Adding fertilizer to your aquarium can help stimulate algae growth, from which the daphnias can feed on.
- Aeration. Daphnias don’t need highly oxygenated water to survive. The reason why we need aeration is to provide water movement and avoid stagnation. Many fishkeepers warn against the use of air stones since they create small bubbles, which are dangerous for the daphnias. There two reasons why air stones are not recommended. First, because tiny air bubbles can get trapped in their carapace, which prevents them from being able to swim as they normally would. Secondly, finer bubbles “scratch” the daphnias repeatedly, causing microdermabrasion.
Then, I add a few shots of Tropica fertilizer to get things going.
Where to Find Daphnia Cultures for Sale
Finding live daphnias isn’t difficult for most.
Most local fish stores will have them available. If not, websites like Kijiji and Etsy can help you find sellers.
Social media, especially Facebook, can be a good place to find other fishkeepers in your area who have daphnias that they’re willing to sell. If you live in a metropolitain area, find fishkeeping associations or discussion groups within your area.
If all fails, you can find them in science education stores, like Merlans or HomeScienceTools.
Prices range between 10 to 20 for about 30 to 50 daphnias.
Prepare your setup before the daphnias arrive. As mentioned earlier, An aged setup is more likely to give you success. If I’m planning on starting a culture, I’ll set up the grow tank 2-3 weeks before I expect to receive the daphnias.
Make sure that the water is clear at all times. This can be achieved with weekly 25% water changes.
Daphnias are highly sensitive to metal ions. It is therefore recommended that you do not use city water when providing a water change. Springwater or mineralized distilled water is recommended.
Daphnias are also extremely sensitive to chlorine, so make sure that your water is properly dechlorinated.
Indoors or outdoors?
Daphnias can be cultured indoors and outdoors. Many fishkeepers maintain a daphnia culture in their backyard. This is a good option for those who wish to grow larger cultures and would like to save space indoors. Outdoors cultures tend to be more stable and be less difficult to maintain.
Indoors on the other hand, can be particularly helpful if you the temperatures of where you live go outside the recommended 19 to 24 C (60.8 to 62.6)
Do daphnias need a heater?
Daphnia’s do best in temperatures ranging between 19 to 24 C (65 to 75F). Generally, daphnias do not a heater. During the winters, my fish room gets cold since the room doesn’t have a radiator. Water temperature can go quite low, between 16-17 C (60.8 to 62.6 F) during the coldest months. I’ll add a heater during those months but otherwise, it’s not needed.