These are Brachionus plicatilis. They are suitable as breeding food for most freshwater fish, larger larvae of marine fish and other sea animals. Its cultivation is absolutely unproblematic and can take place in normal saltwater from 10 ppt up to 60 ppt. It is very important to feed Rotifer with live algae to guarantee optimum nutritional value.
Rotifers eat particulate organic detritus, dead bacteria, algae, and protozoans. They eat particles up to 10 micrometers in size. Like crustaceans, rotifers contribute to nutrient recycling. For this reason, they are used in fish tanks to help clean the water, to prevent clouds of waste matter. Rotifers affect the species composition of algae in ecosystems through their choice in grazing.
In a healthy culture, all the rotifers will be females and will reproduce clonally. In a stressful environment, males will be produced and the rotifers will reproduce sexually and create encysted eggs. Under optimal conditions, rotifer culture will double in the population every day.
Culturing Rotifers instruction can be seen here.