According to John Clare, starter cultures of Daphnia can be mail-ordered from LFS Cultures, Blue Spruce Biological Supply and LarvaTech. Daphnia can also be captured from most lakes or ponds using a fine-mesh net. Purchased or captured Daphnia can be cultured in an aquarium to produce a steady supply of fish food.
John Clare, writing for Caudata, indicates that Daphnia are small crustaceans that are often called water fleas due to their jerky movements. They vary in size from almost 1 centimeter long to less than 1/2 a millimeter in length. There are more than 150 known species in North America alone, with many more distributed worldwide. They live in the debris at the bottom of fresh-water lakes and ponds, where they eat algae and decaying organic matter. In turn, many other organisms eat Daphnia.
According to John Clare, Daphnia can reproduce parthogenically (without sex), allowing the species to rapidly self-replicate under ideal conditions. A single Daphnia can produce 10 clones at a time as often as every three days until the natural lifespan is reached (40 to 50 days). Under less ideal conditions, Daphnia mate and produce fertilized eggs, which can withstand harsh environmental conditions, such as ponds drying up and freezing weather.