Newly hatched brine shrimp measures less than 1 millimeter. An Artemia’s mature size can reach 15 millimeters in length. They normally swim in upsidedown, regularly thumping their legs.
During the first few days after hatching, Artemia feed themselves by consuming their own energy reserves stored in the cyst. Wild ones consume microscopic algae. Cultured ones can be fed yeast, wheat flour, soybean powder, and egg yolk.
Interestingly, their cysts can remain viable for up to 25 years.