When you visit a vernal pool, you can find fairy shrimps. The miniature, shrimp-like crustaceans can be abundant this year, and not exist the next. When fairy shrimps do appear, the active phase of their life cycle is generally short-lived, usually for a few weeks.
Generally, fairy shrimps are permanent residents of vernal or temporary pools. On the global scale, there are around hundreds of species scattered all over the seven continents.
A fairy shrimp is known for its ¾-inch length with a combination of stalked eyes, “upside-down” swimming and color that ranges from red, orange, blue or bronze. Back in the prehistoric times, they populate the oceans but later forced by the evolving predators into shallow, temporary freshwater environments.
Feeding fairy shrimps
In the natural habitat of fairy shrimps, they are considered as filter feeders. They strain miniature particles out of the water for food, mostly algae, bacteria, and even fungal spores.
If kept in captivity, they thrive well on a diet of readily-available starter feeds or you can prepare a “yeast soup”.
Preparing a yeast soup
When preparing a yeast soup, liquify a sachet of dried yeast, either Brewers or baker’s yeast with a tablespoon of sugar and a pinch of pulverized fish food flakes in 1/3 cup of hot water. Make sure that all ingredients are mixed properly and allow to sit for an hour for the activation of the yeast. Choose a container that is tall enough to allow the yeast to bubble up. Store it in a refrigerator or any cool place. This preparation for your fairy shrimps can last for weeks.
When feeding your fairy shrimps, shake or stir the mixture thoroughly. With a pipette or eyedropper, place a few drops into the water. Since they are still tiny, they need minimal food.
There is a rule to remember to determine how much food is enough. Make sure that the water is slightly hazy, but not murky. It is vital that you can see through it. Once it becomes cloudy, stop feeding for 1-2 days until it eventually clears up.
You can increase the amount of food given as they grow. At around 2 weeks, the fairy shrimps will require around 1 ml per day. Once they reach full maturity, they need 3 ml daily.
The water level must be kept constant in the pan. Once the water evaporates, you must replace it with fresh spring water.
Over time, you will notice the formation of “scum” on the water surface. Although this film can be unsightly, it is not detrimental in any way. You can remove it by dragging a piece of paper towel across the water surface.
Once the fairy shrimps reach adulthood, their main objective is to create new eggs. The females will start to produce eggs once they are mature. These white eggs are stored in a transparent pouch attached to their abdomen. The presence of the brood pouch makes it easy to identify the females.
As for the males, they swim around in search for a suitable female. Once the eggs have been fertilized, they will appear bigger and turn into a pale tan color.
The females will thrust the eggs out of their pouch where they sink to the base of the pan. After 1-2 days, the embryos will grow and develop. Once they reach a point of having adequate cells, they become dormant. Take note that they will not hatch until they are fully dried out, chilled and re-wetted.
Hatching fairy shrimps
The ideal way to save eggs to be used for future hatching is to harvest them from the base of the pan. Remove the “gunk” from the base of the pan and pass it through a coffee filter. Make sure that the filter dries out entirely for several days. Once completely dried, fold the filter, label it and store in a freezer until you are going to hatch them again.
If you are going to hatch your fairy shrimp eggs, it is important to start with a clean and bleached pan for the new batch.