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Re: Live Foods Digest V1 #51

>Subject: Re: bleaching BBS eggs to increase hatch


>Anybody heard about bleaching brine shrimp eggs slightly in order to

>vastly increase hatch rates? I always get significantly higher hatches

>after cleaning my hatching containers and air tube with bleach and I

>heard about this at a killie meeting. I need the details on

>concentration and time in solution.


Bleach is used to remove the shells of the eggs, as you know shelless eggs are very expensive.

I have reproduced an article on deshelling Artemia by one of our member who also works as a trout farmer.

Decapsulated Artemia

        By far the best live food you can get for the fish hobby today is live newly hatched brine shrimp.  There are a couple of problems that occur with this shrimp with which I hope I can help, firstly  the dreaded egg shells and secondly, only 6 hours (after hatching) they burn off around 20-30% of their stored energy (that is what you want to feed to your fish, remember from the first hatching to 80% hatch their may take 5 hours, so the brine shrimp that hatched in the first 3 hours will have wasted a lot of energy, so if you leave them even longer the less nutritious they become to your fish.

There is a way of removing the shell of the brine shrimp so when you hatch it you don't have the hassle of siphoning off brine shrimp from the egg shells, this is done by dissolving the shell off the unhatched shrimp in a weak bleach solution, you then either hatch the brine shrimp as normal or feed the unhatched cysts directly to the hungry fish. Remember the unhatched brine shrimp cyst has not wasted any energy on hatching or swimming around the hatching tank, so is by far the better for the fish.

         When you have measured out the amount of brine shrimp eggs you want, put them it to fresh or salt water for 1-2 hours to be hydrated (to absorb water into the egg, as the eggs you get are dried to last longer): then pour the eggs through a fine mesh sieve or net, and you should catch 95% of the eggs, make up a water solution with caustic soda until you have a pH of 10.5 plus (only a small amount of caustic soda is needed, especially in soft water areas).

        Then add 5ml of industrial strength bleach to 1 liter of the solution (1 ppm) but household bleach will do, you will need around 10 -15ml per Lltre, remember it does not have to be exact, but the more bleach you add the faster it works and the less bleach the slower it works.

Add the hydrated eggs to the solution then watch and mix slowly, the eggs Will slowly turn white then turn orange (the time depends on the temperature and the amount of bleach used but is usually around 20 minutes) you then pour the orange cysts back through the sieve or fine mesh net. One problem is that caustic soda and bleach mixed together makes an exothermic reaction (self warming) and if the temperature gets above 40oC you won't he able to hatch them.

Next have a liter of normal tap water, using sodium thiosulphate at a concentration of 0.1% pour it over the cysts to neutralise the chlorine from the bleach then wash under normal tap water, or use one of the branded aquarium de chlorinator`s and wash the eggs 

in this to remove any bleach left on the eggs. If any bleach is left on the eggs it would soon kill the artemia in the eggs or if feed to the fish it could kill the fish.

Smell the cysts to check it's free of chlorine, if you can smell chlorine wash again.

Alan Dunne


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