The Care of Sea Monkeys or . . .
Is the Can More Important Than the Monkey?
by Mike Jacobs

Click to Enlarge All Pictures
All Pictures By Mike jacobs

It is amazing to me that something as common in our hobby as brine shrimp (Artemia salina) eggs (cysts) could be so popular and yet for the most part no one really knows for absolute the proper way to handle them and keep from wasting this very precious resource to the aquarium hobby. I have been hatching brine shrimp (Artemia salina) for the better part of 50 years and I will tell you up front that now it seems I have been dealing with the storage and some of the hatching of the cysts all wrong. There are rumors and bits and pieces of information about brine shrimp cysts storage and hatching but as for really understanding I think there are very few people who are really “in the know”.


Brine Cysts hatched
at 18-24 hours

For several years our killifish club members have been trading tips on hatching the brine shrimp cysts with magic formulas and discussing the problems with buying cans of brine shrimp and whether or not to buy premium, 90% hatch or Grade B cans and talked about is the hatch at the end of the can as good as the hatch at the beginning of the can. Several weeks ago on Killifish E-Mail the usual questions of brine shrimp started to surface again for the “umpteenth” time and there were so many disagreeing stories as to the solution of the various problems with brine shrimp I decided to go to the ‘horse’s mouth’ so-to-speak and to do some old fashion research in an attempt to answer some of the questions of the BRINE SHRIMP CYSTS.

Ok, what do we know? Well, let’s talk about the mundane stuff . . . the information we do know . . . the easy part.

The eggs (cysts ) are of the Artima species of crustacean that is closely related to the local daphnia species. The range of the different Artima is literally world wide and there are several countries have taken advantage of their own salt lakes but the vast majority (93+%) of brine shrimp cysts that are sold worldwide come from the American salt lakes or salt ponds.

The temperature the shrimp seem to be able to survive in is 6– 40 degrees C ( 43- 104 degrees F) however they seem to enjoy and proliferate at 25-30 degrees C ( 77- 86 degrees F). The dehydrated cysts however can tolerate a much wider range than the brine shrimp themselves. It is said that the cysts can tolerate absolute zero (-273° C . . . -459 degrees F) to almost boiling (100 degrees C . . . 212 degrees F). Of course these two temperatures are never even approached in nature but it is interesting to note of the brine shrimp as a species, if those temperatures are correct and they are reached on this earth the brine shrimp seem to have set themselves up to survive most anything and they will far outlast the human species as we know it! There is something very interesting about that!


Cysts siphoned into Brine Net

Salinity also affects the life of the Artima as well and this parameter can also vary widely. (ed note: 0/00 means parts per thousand) The numbers on survival of salinity are not as well defined but have been described as going from “supersaturated” (340 0/00 (1.290 hydrometer reading (specific gravity)) on the high side to “brackish” (80 0/00 (1.060 hydrometer reading (specific gravity)) on the low side. It has been shown that the cysts will hatch from the Great Salt Lake at 2-3 0/00 (1.002 specific gravity) but that in order to be sure of a hatch the salinity needs to be above 10 0/00 (1.008 specific gravity).

The mode of reproduction of the Artima is two fold. They can, under good conditions have live young however when the conditions are not favorable for live birth (low oxygen and/or high salinity) then the thick shelled cysts are left to wait for more favorable conditions. Thusly Brine Shrimp Cysts!

Feeding is not a problem at all for the Artima. They simply eat anything that is suspended in the water as long as it is small enough to get into its mouth. They are indiscriminate filter feeders and that tells it all. The reality of their feeding is they enjoy suspended algae (green water) as a food but has been shown in the aquarium world anything we put in the water will be filtered out of the water and taken into the belly (gut-loading).

The Artima will live for a couple of months if left to their own life time however there is a plethora of predators in the world of the Artima that will make a lunch out of them: Birds, frogs, little fish, bigger fish . . . not to mention the biggest and ‘baddest’ of them all . . . MAN!

There you go. That’s a quick run down on the life of the Artima we all love but now the problem is once the little buggers are harvested how do we, as consumers, deal with the storage and hatching so that we can maximize hatching of the cysts in our aquarium rooms?

Ahhhh, you say . . . it’s easy. 1) Open the can 2) take some cysts out 3) put them in salt water 4) wait 18-24 hours 5) harvest 6) feed . . . well, NOT SO FAST MY LITTLE FISH KEEPING FRIEND!

Storage of the cans of Brine Shrimp cysts: All of the folks I contacted and spoke with (Jehmco (John), Sanders Brine Shrimp (Bruce), Utah Brine Shrimp (Sarah)) said the same thing. Store the cans of cysts in the freezer. The cysts have had the humidity reduced in the can to 7% and frozen to 20-40 below zero Fahrenheit. That humidity and the frozen state are best for the cysts in any long term situation: ‘Long term’ storage being defined as any time over a month. Two of the three companies I talked to had VERY long term studies in progress that amounted to years of being frozen in the can and each passing year there were cysts taken and hatched. The results have shown that the cans that have been in the freezer for 20+ years have maintained the original hatch rate (I want to know the counter and how many fingers he has . . . ;-)).


Newly hatched shrimp in freshwater
before being distributed.

Opening the cans of frozen brine shrimp cysts: Well, here is the first of the real problems. For the almost 50 years I have been hatching brine cysts I never thought about this being a problem . . . it is however BIG TIME evidently and the reason is so simple as to almost be silly! Think of putting a glass of water into the freezer. Wait until it is frozen and take it out and set it on the counter . . . what happens. Think . . . . . . !!! Condensation forms on the outside of the glass. Right? Yes! The same happens with the steaks you have frozen and the chicken parts you put in the freezer . . . take them out and set them on the countertop and BINGO there is condensation forming on the outside of the package. Now picture opening a can of frozen brine cysts and exposing them to the warm high humidity of most rooms . . . relative to the freezer . . . BINGO there you go and it is so simple! Condensation will form on the outside of the can itself AND EACH LITTLE CYST . . . and there in lies the problem!!!!! Once each little cyst is exposed to water, however small, the hatching process begins and that is the problem. Now folks, it doesn’t take 3 gallons of water to start this hatching process. Think how small an individual cyst is . . . it doesn’t take much water (condensation) to start the hatching process. That’s right, according to Bruce Sanders, of Sanders Brine Shrimp, if after the cyst is exposed to the condensation and it is not exposed to the correct HATCHING parameters it STILL begins the hatching process but of course without the correct parameter of the water involved hatching (breaking open the cyst) will not take place but the cyst WILL DIE. Now of course, the whole can is not going to die in a matter of 24-30 hours (hatching time) but Mr. Sanders says that in a typical can of premium cysts that over a period of 4-6 weeks, if opened right from the freezer, you could loose up to 10-15% of the cysts. This explains the observation of 2-3-4 of the SKS crew of guys. We all observed that the end of the can hatch was DEFINITELY NOT as good as the beginning of the can hatch. There are some people that would argue this but I think that their argument is caused by the same phenomenon of your eyesight or hearing going bad. The progression of the loss of eyesight or hearing is so gradual you are not aware of the loss until it really goes bad, but in fact the can of brine shrimp is deteriorating if you open a frozen can . . . ahhhhhhhhhh, there’s the answer. It’s easy . . . don’t open the can in its frozen state! Before you open the can take the can out of the freezer and let it sit for at least a couple of hours until it is completely warmed to room temperature and NOW THERE WILL BE NO CONDENSATION FORMED ON THE CYSTS TO CAUSE THE DEGREDATION OF THE CYSTS. Problem solved by a little logic. By the way . . . when you get the meat home from the store . . . it is almost room temperature isn’t it? Put it on the counter and it will attract NO condensation. It’s not a hard concept but a very important one if not considered. That tip alone should save a lot of cysts for your hatching pleasure.

Now, what do you do with the can once you have gotten it to room temperature? Well, the answer to that varies a little as to how much brine shrimp you hatch. If you use say a can (15-16 oz.) a month. Then you really have two options. Leave the “room temperature” can in a room that is the least humid of your rooms. The fish room would be the worst of those choices. Usually your fish room has the highest humidity of all of the rooms so you are exposing the can of brine cysts to a humidity that, well, quite frankly causes the same absorption of water almost as opening a frozen can . . . especially if you are in high humidity places . . . Florida, thank you!!! How about the refrigerator? The answer was “yes” in all cases but they also all emphasized that this is only for people who intend to use a can in a month. For people who use a can in say 2-3-4-5 months the procedure should be a bit different and it gets a bit complicated. Once opened you should take out what you need for say . . . 2-3-4 weeks . . . and re-freeze the rest of the can. The problem of course is that you now have to go through the un-freezing/freezing process every time you need some more cysts. There will for sure be a bit of degradation when you do this time after time but it is unavoidable and better than opening the can and leaving it open in the refrigerator or out in the room for months; You ARE minimizing the degradation through this process.

Are you getting the point that moisture is the real killer here! Moisture in the form of humidity causes brine cysts to absorb very small amounts of water in the form of condensation and this causes big problems with the cysts. It begins the process of hatching but it doesn’t allow the completion, hatching, of that process and as Bruce Sanders puts it . . . “ . . . once a cysts hits any water it’s all down hill from there!!”

There is so much more to the saga of the Brine Shrimp Cyst. How are you going to maximize the hatch with different water parameters? Does the temperature really matter for a good hatch? Is light necessary for a good hatch? Does seawater help the hatch or is the condition of the cyst and the humidity the key? Decapusalization! All of these will be discussed in the next couple of editions . . . stay tuned for the rest of the story! Next time: HATCHING: The Experts!!!

By the way . . . why “cysts” and not “eggs” . . . simple!

Cyst: A small capsule-like sac that encloses certain organisms in their dormant or larval stage . . . key word here is “dormant”.

Egg: The round or oval female reproductive body of various animals, including birds, reptiles, amphibians, fishes, and insects, consisting usually of an embryo surrounded by nutrient material and a protective covering . . . no “dormancy” is indicated here.

Artemia salina - by Richard Fox, Department of Biology, Lander University
Brine Shrimp - Artemia sp. - by Jean McCrae, Oregon Dept. of Fish and Wildlife
Great Salt Lake Brine Shrimp - by Dr. Ty Harrison, Westminster College in Salt Lake City, Utah
Brine Shrimp and Ecology of Great Salt Lake - by U.S. Geological Survey
Jehmco . . . Aquarium Products . . . http://www.jehmco.com/
Sanders Brine Shrimp . . . http://www.sandersbshrimp.com/
Aquatic Lifeline Inc. . . . Utah Brine Shrimp. . . http://www.ali-artemia.com/