Even if Artemia nauplii have their highest nutritional value directly after the hatching, there are reasons to rear the small crustaceans to become adult Artemia. One is to have real treats for larger fish.
Their rearing is so easy and, as often described, you will have no problem with it.
Take out a small portion of hatched nauplii and put it into a separate container with a large water surface. The large water surface ensures sufficient oxygen intake, otherwise a diaphragm pump with air stone ( JBL ProAir a50 ) needs to be installed. Ideally use 50 % of the old water for that with 50 % newly prepared saltwater ( JBL ArtemioSal ).
Using a pen mark the water level after filling to keep the salinity constant. Evaporated water needs to be replaced regularly with osmosis or distilled water to this marking. If these are not available, use tap water.
Feed the growing Artemia several times a day with a special algae food ( JBL ArtemioFluid ). The algae solution needs to be eaten up within a few hours and should only be sparingly fed. Otherwise the water will be heavily polluted, damaging the nauplii.
The animals become sexually mature after 12 days (at 28 °C) or 22 days (at 20 °C) and they can be distinguished as male and female. With a bit of luck you even can observe the mating. However Artemia can also reproduce when there are only females. It then results in the so-called asexual reproduction (parthenogenesis)