Decapsulated Brine Shrimp
Introduction to Decapsulated Artemia (Brine Shrimp)
Decapsulation consists of chemically removing, in a hypochlorite solution, the shell or chorion of the artemia cysts and leaving only the embryo. The amount of time and temperature when the artemia cysts are exposed to the hypochlorite solution will determine whether the artemia will hatch-out or be non-hatching decapsulated artemia. For non-hatching decapsulation the temperature during the chemical reaction will be greater than 35º C…this is much like hard boiling an egg and removing the shell. The embryo is literally cooked! For hatching or live decapsulation the temperature must remain between 15º-25º C and the reaction quickly neutralized when the solution has achieved the desired results.
Many hatcheries and brine shrimp harvesting companies use decapsulation to get a greater return from lower grade egg. Shrimp and fish hatcheries use their lower grade egg to produce a live or hatching decapsulated egg. While brine shrimp harvesting companies will use their low grade egg (5%-30% hatch rates) that they are unable to sale at market. Brine shrimp harvesting companies usually produce the non-hatching decapsulated artemia, and sale them as a non-hatching ingredient to aquaculture feed producers that make flake and pellet feeds. Non-hatching artemia, however, is also a great feed for aquarium and hatchery users alike. All that needs to be done is to hydrate the non-hatching decapsulated artemia for 8-10 minutes and feed directly to fish or shrimp…this is a very quick and easy way to feed.
Decapsulated artemia offer the following advantages compared to the non-decapsulated ones:
- Cyst shells are not introduced to the predator as they are chemically removed. The shells often become lodged in predator’s digestive track and result in higher mortality rates.
- Decapsulated artemia have higher energy content because they use little or no energy to hatch-out of their shell.
- Due to the hypochlorite solution, the egg becomes thoroughly disinfected, therefore reducing the bacteria introduced in the water and predator.
- Non-hatching decapsulated artemia is a ready-to-use, energy-rich food source.
- The embryo of non-hatching decapsulation has a smaller particle size (200-250 µm) which are more suitable for smaller predators than freshly hatched artemia (400-450 µm).
How to Decapsulate Artemia (brine shrimp)
Decapsulating artemia is a four step process that consists of hydrating cysts, introducing cysts to the chemical reaction, neutralizing and rinsing the embryos after the reaction, and storage or hatching the decapsulated artemia.
You will need to following items:
- Conical container (same as the one used to hatch brine shrimp). An Imhoff cone is ideal and measures 1 liter.
- Aeration supply at the bottom of the cone.
- 1 table spoon of brine shrimp. This may be changed according to your use. Keep in mind we are using a volume measurement as egg weight is affected my moisture content and hatch-out rates.
- 1 liter of sodium hypochlorite or non-fragrance household bleach. Try to find bleach with a higher percentage of solution (5%-13%).
- Brine shrimp net or filter (about 125 µm). Cheesecloth will work fine (about 125 µm).
Salt. This is used for storage only. (live or hatching decapsulation only)
To begin the process of decapsulation, the artemia cysts (brine shrimp eggs) need to be hydrated. When you buy brine shrimp eggs they are dehydrated, thus stopping their metabolism and they enter a stage of diapause or hibernation until hydrated again. These small eggs look dimpled when they are dehydrated.
The decapsulation will be more effective when the egg does not have the dimple. Hydrating the egg will pop out the dimple and make the egg round again.
To hydrate the egg fill the Imhoff cone with 1 liter of warm fresh water (tap water is fine). Turn on the aeration, making sure it is aerating from the bottom. The aeration is used only to agitate the egg and keep it in the water column. If any egg sticks to the sides above the water swish the water around to keep the egg in the water column. Hydrate the egg for about ½ hour. Remember we are just trying to hydrate the egg…not hatch-out the egg.
When hydrated drain the fresh water out of the imhoff cone using the filter (125 µm) or brine shrimp net to catch the egg.
Refill the Imhoff cone with about 800 ml of sodium hypochlorite (bleach). We fill it to only 800 ml versus 1000 ml (1 liter) so there is more room in the cone.
Add the hydrated egg into sodium hypochlorite and aerate again from the bottom. Be sure the aeration is minimal as to reduce foaming. We only need to gently suspend the egg in the solution.
If decapsulatating egg for live or hatching purposes
Carefully watch the coloration of the brine shrimp as this will tell you when to stop and neutralize the reaction. Monitoring the color is very important if decapsulating for live hatchings. The color begins brown and will then change to gray, then white and finally orange. This may take 1-5 minutes depending on the egg (hatch-out, harvest year, etc) and sodium hypochlorite solution…however it is more important to watch the coloration than the minutes.
Once the orange color is reached the reaction must be neutralized. Do this by again rinsing the egg in cold fresh water using the filter or brine shrimp net. Thoroughly rinse until the odor of bleach is gone.
You now have decapsulated brine shrimp eggs. The egg may be immediately fed to your fish as embryos if you did the hatching or non-hatching decapsulation. You may begin the hatching process if you are trying to get a live feed (see how to hatch brine shrimp tutorial video).
To store the decapsulated brine shrimp make a saturated salt solution using a pop bottle. This is done by dissolving as much salt in warm water as you can. You will know when the solution becomes saturated as the salts will no longer dissolve. Store the decapsulated egg in the solution and put it in your fridge. This should keep for several days.