Most common use: Young - adult killies

Daphnia is one of my favorite live foods for my killies because of the easy to keep behavior and the ideal nutrient character. There are many different kinds of daphnia and I culture some of them. All of them are eaten with pleasure by my killies. In the beginning there were many different daphnia species but like any other creature they fight internally. Following most of the daphnia left in the culture is now Daphnia pulex and Daphnia magna.

Zoomed in on my daphnia. Real size is about 2 mm

In most freshwater ponds and water holes you will find some kind of Daphnia. Especially in the summer period. If you go with a very fine meshed net and a bucket you can easily get enough to start your own culture. Please note that it does not always help to bring real large qualities home because only a certain quality will survive in the bucket or in the container at home.
Please note that bringing nature into your tank also means the risk of bringing diseases and parasites to your tank and fish. Following I always avoid to bring home objects found in water sources with natural population of fish. I simply will not take the risk although it in my opinion is quite small.

For culturing at home my best result is in a 20 liter plastic box, filled with rain water and the water from the pond, a small quantity of soil from the garden, some old leaves and grass. I just place it in the garden so it gets the morning sun and I have more daphnia than I can use. I only pour some rainwater in the plastic box once in a while when some has evaporated. The sun and the leaves provides enough algae food for the daphnia's so a constant population is there.
But this is only good in the summer period when we have above 15 degrees. My experience says that below 15 degrees the reproduction rate is going down. Following I have my daphnia in my small unheated (just above freezing) house in the winter season and do not use that many daphnia for live food in this period. I have also tried to bring a culture indoor at place so it gets the sun from the window. My experience says that they will survive and reproduce, but only for the population to survive. I can not get enough for constant feeding.

If you want to have an indoor culture of daphnia I suggest you to find a culture of the Moina macrocopa. This daphnia can easily be held indoor as a culture and will under the right circumstances also reproduce quite quickly. The natural habitat of the Monia is in south eastern Asia where they live in ponds so they are better for the higher temperatures. The Monia is fed with small quantities of bakers yeast and is quite easy to keep.
A very detailed PDF of the Monia can be found here.

As with all live foods I will recommend to have at least 2 running cultures so you always have a reserve if something should go wrong.