Dry Lake Fairy Shrimp

Dry Lake Fairy Shrimp is one of Streptocephalus family member. They live in heavy muddy water of dry lakes during the late spring to the summer. In an excellent condition they can survive in warm water which temperature goes up to 34 C degrees, but the wind always blows on dry lakes and limit the temperature does not go up that much. The fairy shrimps grow up to 13-22mm in length, and usually male shrimps are larger than female shrimps. They are appeared as red-orange, but the food can make changes to the color: sometimes light green, white body with black pattern, or orange. They start to reproduce between 10 to 15 days after hatching, but in fast cases produce eggs in 9 days after hatching. Their life span is normally 3 to 5 weeks, but the longest case is about 9 weeks.

Female fairy shrimps produce eggs (cysts) from dozens to hundreds in their life. Brood sack (egg pouch) is placed on the front of female shrimp's tail. Eggs are developed inside of the body to the tail and the form looks like marshmallow. They are moved into brood sack when developed well, and the shape will be changed like a ball and get thicker membrane as moving into sack, and new eggs will be on the same progress one after another. Eggs are white when they are in the tail and in the brood sack for a day, then the eggs become gray-brown day by day. After about four days moved into the sack the eggs will be released as new eggs are moved into brood sack. Between second to fifth week after hatching is the most active producing period. After fifth week female shrimps produce slowly.

Two type of brood sack (above and below)
Filled with new white eggs (left) and ready to release (right)

Eggs are 170-200 micrometer in diameter. Released eggs fall down into mud at the bottom of lake, and hide from tadpole shrimps (Triops) or any other predators; so most of eggs are under soil when the lake dries up. When it rains again, only a few percentage of eggs are washed out by rain and 70% of them hatch. Usually eggs don't hatch in the water which they were released, they must be dried once to hatch. But there is an exception; if the water is changed to very clean water and exposed to enough sunlight, they hatch out just like when dry eggs are exposed to water. Conversely, there is a case that dry eggs don't hatch when exposed to water; if put eggs to a water pool that has been filled for a long time, the eggs don't hatch and wait for next chance. But in the case when the rain washes dried eggs into the long-time-filled pool, the carried in eggs will hatch out along with a few number of the eggs that were waiting in the pool.

Egg hatching rates

In distilled water : Under direct sunlight about 75% of eggs hatched out. When water temperature had gone down below 59F(15C) for a few hours, eggs did not hatch out. Eggs survived and hatched out very well in the water that had been about 100F(38C) for a few hours.

In tap water : Under direct sunlight about 60% of eggs hatched out. (Warning) Possibly there is chloride in tap water, use with care.

When the egg are exposed to a good condition, they hatch out within 24 to 48 hours (faster one hatches out in 8 hours). Baby fairy shrimps hatch out covered by thin membrane and stay in the membrane for about 30 minutes, then they completely hatch out and immediately swim in the water. Right after hatching baby shrimp is about 0.5 mm long. Within the first day (the day they hatched) they grow to 1 mm. They are white and the center is orange color, and swim like water flea with two legs that placed on the front. On the second day, new legs will be developed behind the first two legs, and the third day, the new legs will be grown to the same size with the first two, and swimming style changes. They will grow to double on the fourth and the fifth day compared to a day before. On the sixth day the gender will be distinguishable, and grow to 8~12mm and keep growing but slowly. They grow almost to the full size in 10 to 15 days, and female shrimps start to produce eggs.


Fairy Shrimp Eggs	Baby Fairy Shrimp in Thin Membrane

Swimming Baby Fairy Shrimp	Baby Fairy Shrimps

Dry Lake Fairy Shrimp in Orange color