Artemia decap

[Luis A M]

There are many strong reasons why artemia cysts should be always decapped (chemically treated to remove their hard shell).Some of these are:
Eggs are sterilized,all pathogen bacteriae usually present in their surface are killed.
Eggs hatch faster,as the nauplii don´t have to work their way out thru the hard shell.
For the same reason,nauplii are more nutritious.
We don´t have to separate nauplii from unhatched eggs and shells,a bothersome and often unsuccessful chore.
The problem of larvae or young fish ingesting and choking with shelled undigestable eggs is avoided.
The mess resulting in acumulating shells/unhatched eggs, is avoided too.
Non hatching eggs,always present in bs eggs,(in different % according to cyst quality) will be consumed as well.

And only one reason for not decapping.All the protocols and techniques given in the bibliography are too complicated for the hobbyist and employ potentially hazardous drugs like Sodium or Calcium Hypochlorite,Sulphuric acid,Sodium hydroxide,and the proceeding must be taken in an ice bath because the reaction produces extreme heat.

But I have been recently experimenting with an old very simple recipe of the 70´s,which I made even simpler.It is so simple and straight forward that I want to share it here.Then,there will be no reason for keep using undecapped artemia!

[KathyL]

Please do share!

In that spirit, here is how I do it:
I put a spoonful of eggs into saltwater and put it into the fridge overnight to rehydrate them.

Next day, add bleach, about half of the volume of the rehydrated egg solution. Swirl for about 10-15 minutes until the eggs turn orange. Filter through a coffee filter, rinse with tap water, add dechlorinator, rinse some more.

Backwash the eggs into a small container with lid. Add about 50-100 ml saltwater. Add salt by the spoonful until no more dissolves. Store in fridge.

I have not noticed the eggs getting warmer. One time, I think I let the bleach stay on too long, and the eggs did not hatch. Other than that time, it worked great.

[C-Aquafarm]

Hello

I just don't decap, but would like to learn a simple way to do it.

[William]

[KathyL]

Luis, please let us know the '70s way!

[David M]

I also use the bleach method, it's simple and I don't see any danger with it. I use an inverted 1 gallon bottle with an airline, soak the cysts in 4 parts FW for 1-2 hours, add 1 part bleach, wait for the color change and rinse 3-4 times using Amquel.

[Luis A M]

Well,it seems there are many people out there who found an easy way to do it!
Kathy went even one step forward and told us how she dehydrates the decap eggs in brine for long term storage

Basically"official"protocols consist of three steps:
1-Hydration Soaking the eggs for some time in FW (Kathy used SW)
2-Decapsulation Brief treatment with hypochlorite-Sodium hydroxide mix,in an ice bath.
3-Dechlorination with strong acids,or thiosulphate (my old recipe used vinegar)

But I found that:
Use of strong alkalis said to keep the pH high,is not needed.pH of bleach is very high naturally,and doesn´t fall during the reaction.
Nor is the use of ice to fight a strong heating of the mix.There is no increase of temp.
And lastly there is no need for dechlorination if the eggs are flushed thoroughly.

So following is the:

DECAP RECIPE

Stong aereation is needed.Decapped eggs are heavier and must be kept in suspension.The commercial hatchers that use inverted soda bottles are ideal.

Soak desired amount of eggs in one part of FW( I use 400ml.) for 1 hr or more.
Add two parts of bleach (800 ml).Wait three minutes.
Pour the mix in a bs net (I use cotton coffee filter bags) and flush under the tap for a while.
Resuspend in half strength SW and put to hatch.

As you see, it is pretty simple.Yet it is a little more work than not decapping if you have to do this everyday.So I put 4 times my daily need (I use 5ml=2.5g/day)and after it is resuspended in 1 L and thoroughly mixed,I siphon out 750ml (under aereation) which I put in three individual 250 ml containers in the fridge.The remaining is completed up to 1L and put to hatch.So I have to decap every 4 days.If I get tired with this schedule,I could split it in 8 days portions.

Hope you find it useful.Let me know if something wasn´t clear enough.
I will stick this thread so any newcomer finds easily how to do it.




[/u]

[KathyL]

[Luis A M]

[sanjay]

[Luis A M]

an obvious safety step,but one more step to do
As I said ,not necessary if the eggs are flushed for a while.A "long" while,10´or more,let them under the tap and go doing something else
Chlorine is negative to smell,to OTO reactive and hatching performance is perfect.

[David M]

I make up 8-10 teaspoons of cysts each time. I use a 1 gallon bottle and rinse using a 6" diameter 125um plankton collector (FAF). I just store them in the fridge in regular SW at about 1.021 SG. They keep just fine but I use them up in a few days anyway.

[Luis A M]

Vicki posted here the simplest (though bizarre ) decap method: http://www.projectdibs.com/forums/showt ... 899&page=2

[Luis A M]

[DanUnderwood]

If you dehydrate the cysts after decapsulation, they will store for several months in the refrigerator. Process is simple, just takes several water changes with 100 % saline solution.

Dan

[KathyL]

or add salt until it no longer dissolves.

[rayjay]

And what do most with the dehydrated cysts, store them in the super saline in the refrigerator or store them "out of liquid" in the refrigerator? I've netted mine out and stored them in a baggie and use a measuring spoon to take out what I want, but then I only decap a cup of cysts at a time.

[DanUnderwood]

I don't think the exact amount of water matters so much, they do need to stay wet. We happen to store them at a rate of 1 can per gallon of brine solution. This is primarily done so they are diluted enough for the average hobbyist to measure out small amounts.

Dan

[aquagrrl]

[DanUnderwood]

Just take a salinity reading on the hatching container.

Dan

[PaulG]

Here is a post that I did for a local Australian Forum regarding how I am decapping artemia cysts.... with pics

I got sick of BBS taking like 24-36 hours to hatch, especially when I needed it a LOT sooner than that so I gave decappsulating a go & so far it has been working for me, I've been doing this for probably the last 5 months now & it saves a LOT of time especially when it comes to collecting the nhbbs & trying not to get any cysts which was taking my 15-20 minutes & even then I would flush almost 1/4 of the nhbbs down the drain.


What you need:
A small bottle for the decapping to occur in (I use a 600ml water bottle).
Bleach, just plain old bleach, the cheapest you can find will do just as good as the brandname stuff.
Timing device.
Filter mesh of no more than 120um in size.
A second small bottle (for storage of decapped cysts)



Pour in enough bleach to the small bottle till there is 1cm of bleach in the bottom of the bottle



I always keep my artemia cysts in the fridge in a sealed container, light & heat will reduce the hatching potential of your cysts over time.


I use a babyspoon to measure out my cysts, at a guess it would probably be 1/3 of a teaspoon of cysts (this is what I would use if I was going to use the cysts immediately).

Why a babyspoon? it fits nicely into the mouth of the bottle :thumbsup:

I should also add.... DO NOT sneeze or blow into the cysts.... if you ever do you'll know why :roflmao:

Once you have added the cysts to the bottle with the bleach, put the lid on, set the timer for 5 minutes


Agitate the bottle containing the bleach & the cysts. DO NOT vigorously shake the bottle otherwise you will end up with lots of foam which will cause issues with the decapping process.
I prefer a simple process of tipping the bottle upside down

and then right way up, taking about 2 seconds each turn. I usually read the forums while doing this.


When the timer goes off, take the lid off the bottle & fill it with tap water


Empty the contents of the bottle out into your filter mesh, if you feel so inclined, fill the bottle u with tap water again & pour it out into the filter to get any remaining cysts






Rinse the cysts in the filter under running tap water until you can no longer smell bleach, this shouldn't take any longer than a couple of minutes & having a purpose built filter such as the one pictured makes this very very easy to do.

Once the bleach smell is gone, I usually place the filter into a bowl with about 2cm of tap water in it & use a turkey baster to suck up all the decapped cysts and squirt them into the second smaller bottle for storage, I then fill this bottle 3/4 full of NSW, put the lid on & store it in the crisper bin of the fridge.

As I need the cysts I grab the bottle from the fridge, give it a shake & pour into a hatching container however much I need & then put the bottle back in the fridge. The hatching container contains full strength NSW, pop in an airstone to make a rolling boil (the decapped eggs will sink so they need a good flow to keep them suspended) 12 hours later (if heated) or 24 hours later (room temp) I have nhbbs, I just suck what I need out with a turkey baster & feed directly I don't worry about washing the nhbbs.

Depending on the strength of the bleach you may need to fine tune the time the cysts are in the bleach, also the more cysts the more bleach you will need & the more time they will need to be in it, don't ask me why but when I have decapped large amounts (5 spoonfulls) it take an extra minute or 2.

If you attempt this & you get no hatch, reduce the amount of time the cysts are in the bleach, if you still have shells in the hatching vessel, give them an extra minute in the bleach.


Why don't I use dechlorinator? no need to. the rinsing of the cysts under running water does a good enough job AND the little bit of tap water left in the bottle does no harm either.


Enjoy!


Edit: I should also add I have stored the decapped cysts in the bottle in the fridge for 5 months & have still had very good hatches, so much so that there are plenty to feed several batched of shrimp larvae.

[Woodstock]

Thank you Paul. Very easy to follow!

[Braddo]

I use here a decapsulated freeze dried brine cysts. These are decapsulated bs eggs that you feed straight to your fry. Have any of you tried these instead of newly hatched brine shrimp?

[PaulG]

Welcome Braddo,

Good to see another face from down under.

The non hatchable decapped cysts are usefull if the fish will take them but most species will not as they will only attack something that is moving or alive.



I should also add that since I had a breeding hiatius I left a bottle of decapped cysts in teh fridge for over 6 months prepared as per my instructions a few posts back.... I through them in a hatching container on the weekend and at least 90% of them had hatched by this afternoon (unheated, water temp was about 16'c). So long term viability of the cysts is possible.

[Braddo]

ok no probs havent tried them on the marines at work yet.
Thanks for the welcome by the way.