|Culturing Daphnia in a Few Easy Steps
This is the inspiration you need to get started with live food culturing. Daphnia are very interesting creatures, but they are also easy and fun to culture under the right condition.
Daphnia (daff-NEE-ah) are small freshwater crustaceans that are found on just about every continent in the world. From the frozen artic to vernal desert pools, daphnia occupy an important niche at the lower rungs of the food web. Most aquatic insects, amphibians, invertebrates, fish and fowl utilize daphnia as a food source. And what an excellent food source they are! Daphnia are high in protein, vitamins A & D, and indigestible chitin (KITE-un) to aid in digestion.
Daphnids have an almost bulletproof reproductive strategy. They have the ability to rapidly clone themselves asexually when conditions are right. When conditions deteriorate, they have the ability to procreate sexually and produce resting cysts that can hatch when conditions improve.
Daphnia are truly hard to beat as a live food culture for tropical fish, mostly because they are so prolific and easy to culture. There are as many ways to culture these little crustaceans, as there are people that culture them. It really is hard to go wrong with these critters. Here are the steps to culturing daphnia:
1) Set up your green water cultures
In a pinch you can feed your Daphnia a very, very small pinch of flour or a single grain of oatmeal. Stir the container and the Daphnia will filter feed the dissolved food in the water. But the best food for rapid growth is green water or single celled algae.
Take some clean plastic storage containers or old used aquariums, and place them in a spot outdoors that gets plenty of sunlight, but not too much direct sun. Fill the containers with some gunky water vacuumed from your fish tanks, and toss in a pinch of natural fertilizer such as blood or bone meal. Some daphnia culturists report having good luck using dissolved Miracle Grow at the rate of 1 teaspoon per gallon of water. An old gallon milk jug is perfect for dissolving the mix. Add in some lettuces and let it rot.
Set up at least two green water containers before you buy your starter culture of daphnia. Allow the green water cultures to become emerald green in color. It’s a very good idea to have duplicate cultures going just in case one of them crashes.
What good is it to take a few weeks storing up a bunch of green water only to have it eaten by the daphnia in a few days? As a rule of thumb, set up at least three times more green water than you need to house your daphnia in. With a couple of containers equaling twelve gallons of green water, you can safely plan on supporting four gallons of daphnia culture. A single gallon container of water can support hundreds of daphnia.
2) Prepare for the arrival of your daphnia culture
Once you have plenty of emerald green water, it is time to transfer some green water culture to the containers that will house your daphnia. To keep a constant supply of green water going, be sure to replace any green water you transfer out of the green water container with tank water or dechlorinated tap water. Try not to use all of your green water up, since it is much more work to start a new culture than it is to keep an existing one going.
For housing daphnia cultures indoors, plastic shoe or sweater boxes work well as does the standard ten-gallon tank. Outdoor cultures do well with 55-gallon drums, plastic tubs or kiddy wading pools. Just about anything that holds water and isn’t toxic can hold daphnia.
It is also a good idea to set up some smaller cultures with a number of different water conditions and different types of containers. Pint-sized drinking water bottles or 2-liter soda pop bottles work well in a pinch. The idea is to hedge your bet by placing your daphnia culture in green water, spring water, treated tap water and whatever else you can think of, to assure that at least some of the daphnia will survive. There is a remote chance that your new arrivals may not take to your green water or your containers may not be daphnia safe. It is better to be cautious by not putting all your eggs in one basket.
3) Acclimate and release the daphnia
Open the shipping box immediately. A few dead daphnia in the shipping bag is normal.
If you notice a marked difference between the temperature of the shipping bag and that of your water containers, you should float the bag for 10 to 15 minutes to equalize the temperature a bit. If both are relatively the same, you can just start divvying up the daphnia amongst the various containers at your disposal. Add a few daphnia at a time, very slowly. Do you see any instant deaths? Don’t put any more daphnia in a container that has them sinking to the bottom to die. Keep divvying them up until they are all spread out among a number of water containers. A dedicated fish room eyedropper works well for transferring the daphnia.
4) Check on your cultures daily
So your new daphnia culture made it through the night in your green water? Good for you! You can start consolidating your mini-cultures into the green water until you have at least two cultures. Again, multiple cultures will help hedge your bet should one of the cultures crash. You will have learned whether daphnia can live in your treated tap water, which is good to know. Daphnia are so sensitive to toxic water that they are used in industry to test for water pollution, sort of like canaries in a coal mine.
Check daily to make sure they have enough green water. Add more as needed, and remember to replenish any outdoor green water containers accordingly if you have them.
5) Care and feeding
If the daphnia eat your green water too fast you may need to set up another green water culture. Daphnia will also eat powdered fish food flakes, bacteria-laden water, and even infusoria from snail droppings. Hikari “First Bites”, “Liquifry”, “Spiralina Powder” and “Cyclop-Eeze” are great foods to supplement your green water as well. Care must be taken not to over feed or pollute the daphnia culture water.
Daphnia populations are known to pulse (rise and fall). A lot depends on water quality, available oxygen, light duration, and available food sources. Some trial and error and experimentation is in order with regard to light duration, added air bubblers and amount of food to offer. By and large, leaving the light on all the time will help promote algae and bacteria in the culture, and an air bubbler (no airstone!) will keep water circulating. The ambient temperature should be kept in a range that is comfortable for people. Outdoor cultures can be pretty much left to their own devices.
If you fear your culture is crashing (you start to see a lot of dead daphnia), remove 10% of your culture water. Then add fresh conditioned water and some food to the container. Also, harvest some of the daphnia to start a new culture, and/or provide a heavy feeding for your fish.