about artemia, an important larvae feed

The common brine shrimp (artemia) is in the phylum Arthropoda, class Crustacea. Artemia are closely related to zooplankton like Copepods and Daphnia, which are also used for live food in the aquarium. The artemia life cycle begins by the hatching of dormant cysts which are encased embryos that are metabolically inactive. The cysts can remain dormant for many years as long as they are kept dry. When the cysts are placed back into salt water they are re-hydrated and resume their development. Artemia cysts are best stored in a tightly sealed container in a cool, dry environment. The refrigerator is usually best. After 15 to 20 hours at 25 degrees C (77 degrees F) the cyst bursts and the embryo leaves the shell. For the first few hours, the embryo hangs beneath the cyst shell, still enclosed in a hatching membrane. This is called the Umbrella stage, during this stage the nauplius completes its development and emerges as a free swimming nauplii. In the first larval stage, the nauplii is a brownish orange color because of its yolk reserves, newly hatched artemia do not feed because their mouth and anus are not fully developed. Approximately 12 hours after hatch they molt into the second larval stage and they start filter feeding on particles of various microalgae, bacteria, and detritus. The nauplii will grow and progress through 15 molts before reaching adulthood in about 8 days.