The Amazing Brine Shrimp by Jim Quarles originally published in "Our Discus" North American Discus Society's publication July 1993.

We, as discus breeders, hatch and feed millions of brine shrimp all the time, but have you any idea just how wonderful and strange these little life forms are?   Brine shrimp are not closely related to real shrimp.   They are Branchiopoda, a specialized branch of Crustacea that includes water fleas.

The simple small sea monkey has a long and quite unbelievable history.   Few species of any kind can survive in ecosystems that provide ideal conditions for the brine shrimp.   With few exceptions even small planktonic organisms suffer fatal dehydration.   The osmotic pressure would extract water from their cells causing a quick death, but the Artemia has a built in system for pumping out the excess salt from its system.   Brine shrimp thrive in ponds where the salinity is high enough (5 to 25 percent) to exclude fish predators.   However, their life cycle can only be completed in a narrow range of 5 to 20 percent.

Few of us in the tropical fish hobby realize that the little brine shrimp is one of the world's best filters.   That's right, a perfect swimming filter unit.   Since they are filter feeders they continuously remove algae and debris from the water and therefore increase water clarity.   This allows more light to be absorbed by the pond bottoms and thus increases evaporation.   The increase in evaporation in turn increases salt deposits.   If the brine shrimp is not present by nature in areas where salt mining is done, stocking them will help salt production.

Some populations are entirely females and reproduce by parthenogenesis.   This means they only reproduce without males present and all individuals are females.   This reproduction results in almost identical clone’s generation after generation.   There are several strains of this species and are found mostly in Europe.   With this type of reproduction the species has reached an evolutionary dead end street.   This is because they are incapable of sexual recombination that is the key to adaptability and survival.

In the New World three sexual species of Artemia occur. A. persimilis is found only at Hidalgo, Argentina.   This species is isolated from other sexual species by an additional pair of chromosomes and therefore cannot crossbreed with other species of brine shrimp. A. monica is found only at Mono Lake, California. This species seems to require a high level of boron in the water.   A. franciscana has natural populations scattered throughout North and South America.   Almost 100% of the eggs sold in the United States are A. franciscana and come from the Great Salt Lake area of Utah and the San Francisco Bay in California.   For completeness there is two additional species that occur in the Old World. A. tunisiana and A. urmiana.

The franciscana species has been introduced by humans in Southeast Asia, Australia, New Zealand and has been found in Spain and Kenya.   Many fear that like many exotics, A. franciscana will displace native populations of brine shrimp.

The female brine shrimp carries the eggs that develop into cysts.   The cysts can survive for a proven period, of up to two thousand years, and still hatch.   The brine shrimp has been known for years as a source of great food for our tropical fish.   However, it should be pointed out that while newly hatched brine shrimp is almost a perfect food for most tropical fish fry,   frozen brine shrimp, adult or in baby form, is next to useless as a food source.   Fresh live brine shrimp should be fed when it can be obtained.   Once frozen however it loses most of its value as food.

So the next time you drop the little brown eggs into that bubbling salt water bath take a moment to reflect on the wonder of life you are about to start.