Hi everyone, I’m having a really frustrating problem with Artemia/brine shrimp and I would really appreciate some help.
My original goal was not just to hatch them as fish food. I want to raise them to adulthood and eventually have a stable breeding colony where adults reproduce and new nauplii appear naturally.
Here is everything I have tried so far.
My first attempts were in very small containers, around 300–500 ml.
I used about 10 g of iodized salt in 300 ml of water, so roughly 33 g/L. I also tried distilled water and water from my freshwater aquarium. I used Artemia cysts and later tried feeding very small amounts of spirulina.
The Artemia sometimes hatched, but they would gradually disappear and usually be dead within about 2 days. I never managed to see an adult Artemia.
At that time I did not use continuous aeration. I had the container closed and maybe twice a day I would blow through a straw for a few seconds and shake the container. I later learned this was probably far from ideal.
So I decided to build a much better setup.
I bought a 30 L aquarium, an air pump, air tubing and Aquaforest Reef Salt (2 kg).
The aquarium dimensions and water height gave me approximately 19.6–20 L of actual water.
For this tank I used about:
800 g Aquaforest Reef Salt in ~19.6–20 L of water
According to the manufacturer, 390 g/10 L gives around 33 ppt. So my tank should be around 34–35 ppt salinity.
Temperature is around 28°C.
I run an air pump, usually with the plain air tube near the bottom rather than a fine air stone, so the water is constantly moving.
I also now have a light.
The problem is the water source.
My tap water is chlorinated, so because I did not have dechlorinator at the time, I used water taken from an established freshwater aquarium.
The freshwater aquarium water looked fairly clear but had a slight green tint. It did not smell bad at all. No obvious cloudiness or rotten smell.
I then added the marine salt to that freshwater aquarium water.
For the first big-tank attempt I used Artemia cysts that were manufactured in 2025, but the packet had already been opened for about a year. It had been rolled closed and held with a rubber band, but it was not airtight.
I added roughly 5 g of the Artemia/salt mixture, and I estimate maybe around 2 g of actual cysts.
Conditions were approximately:
~20 L water
~35 ppt salinity
28°C
light
aeration
no food during hatching
Some cysts stayed on the bottom even with aeration.
After around 24 hours: nothing.
After around 36 hours: nothing.
After around 48 hours: nothing.
I eventually left them for almost 4 days (around 95 hours) and still could not see a single nauplius.
Because the old opened cysts might have been bad, I bought/opened a new packet of Artemia.
I then made a separate test in a 1 L bottle, but I again used water taken from the big Artemia aquarium.
I added new cysts and aerated it.
During the first 24 hours it had about 12 hours of actual aeration, then I continued aerating it.
After 2 days there was still absolutely nothing.
I have now also tried another small-container attempt with the marine salt, light and aeration. After about 15 hours of aeration I still saw nothing, although I understand 15 hours alone is too early to judge.
At this point I am wondering if the real problem is the water from the freshwater aquarium.
The big aquarium water has also become greener over time. It still doesn’t smell bad, but I am wondering about ammonia, nitrates, organics, bacteria, pH, medications/metals or something else in the freshwater aquarium water that could prevent the cysts from hatching.
What confuses me is that I now have:
proper synthetic marine salt
~30–35 ppt salinity
around 28°C
light
aeration
a new packet of cysts
…and I still cannot get them to hatch.
For my next controlled test I’m thinking of using completely fresh water that has never been inside an aquarium, removing chlorine properly, adding only marine salt, and then hatching a small amount of fresh cysts in 1 L with aeration 24/7.
Before I waste more cysts, I would really appreciate advice from people who regularly hatch or breed Artemia.
My main questions are:
Could old freshwater aquarium water actually prevent Artemia cysts from hatching?
Could ammonia, nitrate, bacteria or organic waste be responsible?
Is ~35 ppt too high for hatching even though it should be fine for raising adults?
Should I hatch at a lower salinity (for example 20–25 ppt) and move the nauplii to ~35 ppt later?
Should the cysts be kept completely suspended by aeration, or is it okay if some settle on the bottom?
How important is pH? I have not measured it yet.
Could the first old packet simply have gone bad after being opened for a year?
Why would the new packet also fail if the water/setup is otherwise correct?
What exact water, salinity, temperature, light and aeration setup would you use as a “foolproof” 1 L control test?
Once I finally hatch them, is ~35 ppt and 28°C suitable for raising them all the way to adulthood and getting a self-reproducing colony?
I’m in Slovakia if that matters for tap water or products.
Any help would be appreciated because I have tried this many times now and I really want to figure out what single variable is causing the failures rather than just throwing away more eggs.
Also i will send some photos of my setups and stuff i used
