They are daphnia pulex wild collected I Began collecting and cultivating my own live foods 30 years ago and with more than 30 tanks of live- bearing fish , i needed to cut the cost of buying prepared foods back in the day most LFS shops sold live foods and I soon learnt that live food was and is very beneficial
Try to avoid collecting daphnia from ponds with water birds or fish in. Ponds that dry up over summer are the best. Go there in winter and spring and you can usually see clouds of daphnia moving through the water.
Get a 10-12 inch fine mesh fish net and move it a figure 8 motion in a pond.
Put contents in a white bucket with water from the pond.
Check bucket for unwanted things like dragonfly larvae.
Take daphnia home and put in a container of green water.
Scoop baby daphnia out and put in a new container of green water. Do this for several batches of young to help get a clean strain that is free of parasites that can infect fish.
The following link has info on culturing green water and infusoria, which daphnia will feed on.
STARTING OUT Make sure you have a pair, (1 male + 1 female). There is nothing worse than spending your hard-earned dollars buying a couple of fish to try and breed and ending up with a pair of fish of the same sex. Let's face it, to reproduce fish you need a male and a female. Two males won't do...
The easiest method to culture daphnia is to use old fish tank water so when i do a water change i pour the water into large bucket or container when i have a fish tank going through an algae Bloom i use the green water it's also beneficial. once container is filled with the fish tank water i just had a few daphnia,
Daphnia cultures can be kept almost any where and In any suitable type of container. I have cultures in my fish room and outside in water butts.
When feeding i use one of two methods i boil spinach liquidise it and use both the spinach and boiled water then slowly pour into the daphnia culture.
The second method is less time consuming is to feed brewers or bakers yeast i add 1 teaspoon of yeast to a jar of water mix until it goes milky then slowly pour into water until it goes slightly cloudy the daphnia will start feeding straight away and after a few days the water will start to clear i then repeat process several times before harvesting
list of live foods that I culture
earthworms, white worms, grindal worms, microworms,
other live foods. flightless fruit flies, vinegar eels, daphnia pulex, daphnia moina,
all of above are easy to culture