Fairy Shrimp are normally gray-white and transparent. They have a long bodies with 11 pairs of legs. Females have a pouch for holding egg, right behind the legs. Fairy shrimp are branchiopods. They are usually found in in vernal pools. Even though they live in fresh or saltwater they do not live in oceans or seas. Even though most fairy shrimp are small , the largest ones are over 6 inches long and eat other fairy shrimp. 
The body of a fairy shrimp is seperated into the head, thorax, and abdomen. The head has two sections, the first has the antennae and eyes, and the second one has the jaws. The males use their antennae to hold females, while mating.
In most fairy shrimps the thorax has 11 segments, some have 17-19 segments. Every segment has a pair of legs, and every leg has 2 or 3 lobes on the outer side, those are for the breathing organs, and paddling. On the inside there are 6 lobes that push the water into the mouth. 
While mating, the male shrimp swims under the female and holds on to her with his antennae. He could hold on from minutes to days. The eggs are put by the female into her egg sac, 2 to 3 days after mating, next they are dumped into the water and they will sink to the bottom, where they will start to develop. 
The Fairy Shrimp are filter feeders. They use their legs to collect algae, bacteria, and protozoa floating in the water. The food is filtered from the water and is eaten by the mouth. The legs are also used for taking the oxygen it needs from the water. Fairy shrimp have few predators, because Fairy Shrimp live in wetlands there aren't any fish that would eat it. 
Fairy shrimp live in a large, cool-water vernal pools, these are filled by the rain in the rainy season. The Shrimp leave the vernal pools before it dries up.
 A vernal pool is "a seasonal wetland area that supports the spring growth of certain specific species. In the winter vernal pools may be frozen over after having been filled with fall rains." 
Scanning electron micrograph of a fairy shrimp nauplius larva (about 7 hours old).