The Complete Guide to Artemia (Brine Shrimp)

By Mike Gilbert and Bethany Watson

Newly hatched brine shrimp, or artemia, are used as first foods for most species of seahorse young. The artemia should be enriched however with a HUFA booster such as Selco. The newly hatched brine should be allowed to age for 12 to 24 hours prior to enriching. When first hatched, they do not have a complete digestive system and therefore cannot be enriched. After the 12–24 hour period their digestive tract is developed allowing them to take in the enrichment. I have the best results enriching for 12 to 24 hours. I have 3 hatcheries setup, the first is to hatch the cysts, the second to let them grow and the third to enrich. If the brine is properly enriched good results can be achieved with most seahorse species.

Another common problem is separating the shells once the brine is hatched. The easiest and best method in my opinion is decapsulation. Aside from eliminating the shell, decapsulation sterilizes the cysts and can increase hatch rates if done properly.

Decapsulation:

Materials needed:

  • Brine shrimp net
  • 2 tsp Artemia cysts
  • 2 cups of luke warm water
  • 2/3 cup of regular bleach
  • Air pump and airline tubing
  • Cloths Pin (to hold airline)
  • Sodium Thiosulfate (Dechlorinator)

Removing the outer shell from an artemia cyst has many benefits. First of all it prevents any unwanted contaminants (hydroids, etc.) from entering your rearing system. Secondly there is no need to deal with the shells after the artemia hatches, and last but not least the newly hatched artemia are much higher in nutritional value because they haven't had to use all their resources to break out of the shell. The following method is the one we use and it can be scaled up to however much you need to hatch. The decapsulated cysts can be stored in the fridge for about a week and still work well.

Step 1:

Add 2 cups of luke warm water to a suitable container (a jar or plastic container work well). Clip the airline to the edge and make sure that it is all the way to the bottom of the container, so it really bubbles the water. You want the cysts to stay in motion. Add 2 teaspoons of cysts, and wait one hour, washing the cysts off the side occasionally with an eye dropper (just suck up a little water from the container).

The cysts hydrating

Step 2:

After one hour the cysts are hydrated. The following images show the difference between dehydrated and hydrated cysts:


Dehydrated

Hydrated

At this point we are ready to decapsulate. Add 2/3 cup of bleach to the container and watch closely. There will be three color changes. First they are brown, then light gray, then orange. When they reach the orange stage they will need to be immediately poured in to the brine shrimp net and rinsed with cold water. Pour dechlor over them as well to neutralize the bleach. An easy way to check the cysts is to pour a little through the brine shrimp net and see what they look like. You want to see mostly orange, but a few gray ones. If you over bleach them they will not hatch, so it's better to stop the reaction at this point. The following images show the color change at 30 times magnification:

A few orange cysts
About half and half
The cysts after rinsing

The amount of bleach can be increased or reduced to increase or decrease the speed of the process.

Step 3:

After thoroughly rinsing the cysts until no odor of bleach remains, squeeze the net to remove as much water as possible and place them into a sealed container. Place this in the fridge and use what you need daily. The cysts should last at least a week.

Hatching:

Hatching artemia takes about 24 hours. After they are hatched, we give them another 24 hours to reach the next stage in their development, called the Instar II stage. At this point the artemia is capable of ingesting food or nutrients. We enrich all ours with a HUFA booster such as Selco. This is necessary as seahorse fry generally doesn't do well on unenriched artemia. We use three "hatchers". One is where the actual hatching takes place, the next is a holding "hatcher" to wait until they are at Instar II, and the third is the enrichment "hatcher".

If you use decapsulated cysts, you must have A LOT of bubbles in the hatcher. Decasulation removes the shell which in turn takes away their ability to float. If you don't have enough circulation in the hatcher, you'll end up with clumps of cysts.

Building a Hatcher:

A simple hatcher to use is constructed of two 2 liter pop bottles. Cut the top off of one bottle and the bottom off another as shown below:

Next, drill a 1/4" hole through the cap, run the airline about 1/2" in and seal with epoxy on the outside. Epoxy is available at most hardware stores. Drill a hole through the bottom half of the bottle for the airline to pass through, and put the two halfs together.



The completed hatchery

Enrichment:

To enrich adult artemia (brine shrimp) simply place the enrichment media, being algae paste, Selco, etc. in with the shrimp. For adult shrimp this can be done at any time by simply feeding the tub they're stored in. Do not, however, do this with a HUFA booster such as Selco. This will spoil the water and may kill all your brine. To enrich with a booster, use a seperate container such as the hatcher described above.

To enrich newly hatched artemia, place the enrichment media in the hatcher after the shrimp are 24 hours old. We enrich for 12–24 hours.

Most recent revision: 2002

Copyright 2002–2004
Mike Gilbert, Bethany Watson & Seahorse.org
All Rights Reserved


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