General Info.

Brine shrimps, or artemia, are a zooplankton used mainly as fry food, but they can also be grown to about 20 mm (0.8 inch) in length and be a valuable food source for adult fishes as well. What makes brine shrimps such ideal fry food is their good nutritional value, their ability to live 5 hours in fresh water before dying, and the fact that the eggs can be stored for many years as long as they are kept away from water and oxygen. Once the dried eggs are returned into oxygenated saltwater they resume their development and hatch. This is an adaptation to living in desert lakes that dry up.

The time it takes them to hatch depends on the temperature. It takes 15 to 20 hours at 25C (77F). A higher temperature shortens hatching time. The optimal hatching temperature depends on the origin of the brine shrimps, however temperatures between 25-30C (77-86F) are recommended.

- Recommended salinity: 30-35 ppt (1.022-1.026 density)
- Recommended pH: 8.0 (pH 6.0-9.0 is acceptable)

Once they hatch they enter the umbrella stage, during which the larvae do not feed since they haven't yet developed a mouth or anus. They survive on their yolk sac during this time.

After 12 hours they enter the second stage of development and start feeding by filtering micro-algae from the water. The nauplii grow fast, and can reach adulthood in 8 days. Brine shrimp can live for up to 3 months.

Since this article is focusing on growing brine shrimp to adulthood, I shall not address the question of how to hatch brine shrimp.

Caring for your brine shrimp

There are several factors that contribute to the successful raising of brine shrimp to adult size. The two most important ones, besides giving the brine shrimp the above stated water parameters, are:

Feeding: brine shrimp are not hard to feed. They accept most food they can filter out of the water as long as it's not too big and doesn't dissolve in water. There is brine shrimp food available in pet stores, containing micro-algae for the nauplii to eat. There are, however, quite a few cheaper alternatives that you can buy in your regular grocery store; for example yeast, wheat flour, soybean powder and egg yolk. It's hard to know how much to feed the nauplii, but the transparency of the water can be of help. During the first weeks you should be able to see about 15 cm into the water. When the nauplii grow, the food concentration should be kept a little lower, and a water transparency of 25 cm is recommended. Food levels should be kept constant, so frequent feedings are required.

Aquarium maintenance: Brine shrimp are usually kept in small tanks, and therefore water quality may deteriorate quickly. Water changes are of utmost importance. I recommend changing at least 20% two times a week. This is to prevent low oxygen levels which will be a result of poor water quality. It's also important to clean the bottom of the tank since brine shrimp moult very often during their way to adulthood, leaving a lot of remains on the bottom of the tank which may lower the water quality. Cleaning should be done at night using a flashlight to draw the brine shrimp to the surface. Brine shrimp are drawn to light, and the light from the flashlight will attract them to the light source, keeping them safe while you clean the bottom of the tank.

Breeding brine shrimp

If well cared for and kept in a low salinity, your adult brine shrimp will (or might) spawn in your aquarium. Every adult female is capable of producing 75 nauplii a day, or 300 every 4 days. They will be able to spawn 10 times during a normal lifespan. However if well cared for they can, as I stated earlier, live for as long as 3 months and during that entire time spawn every 4 days.