The Order Anostraca is a group of small, freshwater crustaceans commonly known as fairy shrimp. They are characterized by elongated, segmented bodies, numerous leaf-like legs used for swimming and filter feeding, and the absence of a carapace. Anostracans are typically found in temporary pools, vernal ponds, or hypersaline environments, where they survive harsh conditions by producing drought-resistant eggs called cysts. They feed on algae, bacteria, and detritus, playing an important role in aquatic food webs. Many species have adaptations for extreme environments, such as rapid life cycles and tolerance to high salinity, making them key indicators of ecological health in ephemeral freshwater habitats.