Artemia (Brine Shrimp) FAQ 1.1
Artemia FAQ 1.1
Having seen all the posts about brine shrimp questions, I have decided
to create a FAQ for artemia culture. It is by no means the definitive source,
and will be expanded on in the future. I have gathered this information
from various books, publications and my own experience in raising these
guys. I have tried extremely hard to make sure I put everything in my own
words so as not to plagiarize. If you recognize a sentence here and there,
its because there really isnt a better way to say it. There is a wealth
of information out there that gets real scientific, much of this I have
left out as it really doesnt pertain to our goal of growing these critters.
Anyway, here it is, hope you find it to be of use. Any comments or additions
to this FAQ should be directed to me. Kai Schumann (KS@Lilly.com)
The common brine shrimp (artemia) is in the phylum Arthropoda, class
Crustacea. Artemia are closely related to zooplankton like Copepods and
Daphnia, which are also used for live food in the aquarium. The artemia
life cycle begins by the hatching of dormant cysts which are encased embryos
that are metabolically inactive. The cysts can remain dormant for many
years as long as they are kept dry. When the cysts are placed back into
salt water they are re-hydrated and resume their development. Artemia cysts
are best stored in a tightly sealed container in a cool, dry environment.
The refrigerator is usually best.
After 15 to 20 hours at 25 degrees C (77 degrees F) the cyst bursts
and the embryo leaves the shell. For the first few hours, the embryo hangs
beneath the cyst shell, still enclosed in a hatching membrane. This is
called the Umbrella stage, during this stage the nauplius completes its
development and emerges as a free swimming nauplii. In the first larval
stage, the nauplii is a brownish orange color because of its yolk reserves,
newly hatched artemia do not feed because their mouth and anus are not
fully developed. Approximately 12 hours after hatch they molt into the
second larval stage and they start filter feeding on particles of various
microalgae, bacteria, and detritus. The nauplii will grow and progress
through 15 molts before reaching adulthood in about 8 days. Adult artemia
average about 8mm long, but can reach lengths up to 20mm in the right environment.
An adult is a 20 times increase in length, and a 500 times increase in
biomass from the nauplli stage.
In low salinity and optimal food levels, fertilized females usually
produce free swimming nauplii at a rate of up to 75 nauplii per day. They
will produce 10-11 broods over an average life cycle of 50 days. Under
super ideal conditions, an adult artemia can live as long as three months
and produce up to 300 nauplii or cysts every 4 days. Cyst production is
induced by conditions of high salinity, and chronic food shortages with
high oxygen fluctuations between day and night.
Adults can tolerate brief exposures to temperatures as extreme as -18
to 40 degrees C (0-104 degrees F) Optimal temperature for cyst hatching
and adult grow out is 25-30 degrees C (77-86 degrees F), but there are
differences between strains, San Francisco bay strain is 22 degrees C as
compared to 30 degrees C for Great Salt lake. Artemia prefer a salinity
of 30-35 ppt (1.0222-1.0260 density) and can live in fresh water for about
5 hours before they die. Caution should be used to not over feed in a fresh
water aquarium because of the rapid decomposition of the dead. Many fresh
water fish will tolerate and even thrive in a brackish water environment
of 1-5 ppt easily, so it is possible to add saltwater to the tank and extend
the survival of the artemia if required.
Other variables of importance are pH, light and oxygen. A ph of 8-9
is best; pH less than 5 and greater than 10 will kill the culture. the
pH can be increased with baking soda, and lowered with muriatic acid. A
minimum amount of light is necessary for hatching and may be beneficial
for adult grow out. A standard grow lite bulb available in an aquarium
supply is adequate. Most important is the level of oxygen in the water,
as this dictates what the artemia will consume. With a good oxygen supply,
the artemia are a pale pink or yellow, or if they are heavily feeding on
microalgae they will look green in color. In this ideal condition growth
and reproduction is rapid, and a self-sustaining artemia supply is possible.
If there is a low oxygen level in the water with large amounts of organic
matter, or a high amount of salinity from evaporation, the artemia will
feed on bacteria, detritus and yeast cells, but no algae. It is under these
conditions that they produce hemoglobin and look red or orange in color.
If this environment remains they will start producing resting cysts, and
the colony may crash. It is very important to have a vigorous air supply
in the tank for two reasons, one is to keep the available food supply in
suspension where it can be filtered out, and the other is to promote a
good oxygen supply in the system. (in other words - a boiling cauldron
The optimal conditions for hatching artemia are as follows - 25 degrees
C, salinity - 5 ppt (1.0030 density), heavy continuous aeration, light
- 2000 lux constant illumination, pH 8-9. Good circulation is essential
to keep the cysts in suspension. A container that is V shaped is best (two
liter bottles work good, the absolute best Ive found are separation columns
found in any lab supply - theyre expensive though). glue a valve on the
cap and invert, this way unhatched cysts, empty shells, and hatched nauplii
can be easily removed separately. Another idea I would highly recommend
checking out was offered by Ken Cunningham (firstname.lastname@example.org). His discovery
was to use pilsner beer glasses, Some of them have a conical point at the
bottom, these are the ones to look for. Ken places three or four in a ten
gallon tank and heats them by the water bath method. Put rigid air lines
in the glasses with no air stones, connected by flexible tubing to the
distribution manifold. 80 degrees, bright light at all times. In each glass
put 1/2 teaspoon of salt, 1/2 or 1/4 teaspoon of cysts, and bubble for
24 hours. To harvest, leave the rigid tubing in the glass, but lift it
out of the aquarium and disconnect the flexible air tube at the manifold.
Let the glass settle in relative darkness (i.e. not bright light) for 10
minutes, and siphon the artemia out using the airline tubing into fresh
water to rinse. By using the glasses on a rotation, its possible to have
hatched artemia available at all times. Still another good idea comes from
Wright Huntley (email@example.com) who originally got the idea from
Oleg Kiselev. Wright now uses Chianti wine bottles found at Trader Joes
for 4 bucks. By tilting the bottles on edge and using the same salt and
cyst ratio as Ken, quite high hatch rates are being obtained. harvesting
is the same, by siphoning using the air tubing, but into a funnel lined
with a handkerchief, then the artemia may be rinsed if desired, and fed.
There are many methods in use for hatching these guys. Once you play with
whatever particular method you chose to achieve optimum performance, your
results will probably be just as good as any other hatching method. Dont
be afraid to experiment.
The hatching percentage and density are usually a function of water
quality and circulation. Containers with flat bottoms have dead areas in
the corners and are not ideal for maximum hatch rates. It doesnt take alot
of cysts to get going, there are usually 200,000 to 300,000 nauplii per
gram of cysts, so a half teaspoon in a two liter bottle is more than enough
for the typical aquarist. With a setup of two or more bottles, one started
one day, the other the next, you can have a continuous supply of newly
hatched artemia for that reef tank every day. This is the method we used
when I worked at Scripps Aquarium - only with 5 gallon water bottles.
Harvest the nauplii by turning off the air, or remove the air stone,
and let the culture settle for about ten minutes. Hatched, empty shells
float to the surface, and unhatched cysts will sink to the bottom. The
newly hatched nauplii will concentrate just above the unhatched cysts on
the bottom. Since the newly hatched nauplii are attracted to light (phototropic),
by shining a flashlight at the center of the bottle, you can concentrate
them where it is easy to siphon them off, or drain the cysts off the bottom
by using the valve, then drain the nauplii onto another container. The
unhatched cysts should be used in the next culture and not thrown away,
most of the time they will hatch with the next batch.
Since artemia are non-selective filter feeders (meaning they dont care
what they pick out of the water), a wide range of food has been successfully
used. The criteria for food selection should be based on particle size,
digestibility, and solubility (powdered milk wont work). Feeds that have
been used include live microalgae such as nanochloropsis and a wide variety
of inert foods, which are far more practical for us aquarists. One caveat
with inert foods is to be careful not to overfeed. Inert feeds include
yeasts, both active and inactive (a brewers supply is the best source,
bread yeast is expensive!) micronized rice bran, whey, wheat flour, soybean
powder, fish meal, egg yolk, and homogenized liver. ( I havent used the
last four). Dried microalgae such as spirulina has also been used with
success (available from health food stores, but again kind of expensive).
The simplest way to measure food levels in the tank is by figuring the
transparency of the water. This is done with a dowel with measuring marks
marked off in centimeters, and a white disk glued on the end. The depth
where the white disk just disappears measures the light penetration into
the tank. The more stuff floating around the tank, the less transparency.
With a stocking density of 5000 nauplii per liter, the transparency should
be 15-20 cm the first week, and 20-25 cm thereafter. Of course it is best
to maintain an optimal food level at all times, so frequent feedings, or
better yet, a continuous drip feeding are mandatory for optimal grow out.
Food is not directly consumed, but rather transferred to the mouth
in a packaged form. The space between an artemias legs widens as the legs
move forward. Water is sucked into this space from below, and small filtering
hairs collect particles including food from the incoming stream. On the
back stroke the water is forced out and the food remains in a groove at
the base of the legs, this groove has glands that secrete an adhesive material
that clumps the food into balls, and microhairs move the food packages
toward the mouth. The optimal size for food should be less than 50 - 60
microns. Growing Adults - When feeding larger fish and invertebrates where
small food is not needed, adult artemia may be preferred over nauplii.
But why should you bother growing adults you ask? I will just feed more
newly hatched brine shrimp to make up the difference you say... Well, adult
artemia are 20 times longer and 500 times heavier than nauplii and therefore
provide more of a meal. There is a myth floating around that adult artemia
are not as good for your fish as newly hatched. There is a tiny bit of
truth to this, but it depends on what you are feeding. So whats in it for
your fish: Newly hatched artemia are high in fats, about 23% of dry weight.
By mid juvenile stage, the fat levels have decreased to about 16 %, and
by the time they are pre-adults the fat levels have decreased to about
7%. But, at the same time, the protein content has risen to replace the
fat, from about 45% in a newly hatched artemia to about 63% in an adult.
Based on this, you should determine what is best for your tank, young fish
larvae require a high fat intake for growth and health, while older juveniles
and adults need protein for health and reproduction. Also, nauplii are
known to be deficient in several essential amino acids, while the adult
artemia are rich in all essential amino acids. Adult artemia therefore
supply more biomass than nauplii and are more nutritionally complete.
The best approach to growing adults is to pick up a 10 or 20 gallon
glass aquarium cheap someplace. Take thin acrylic sheet or formica, and
jam it in the tank, essentially making an oval tank. ( this is important
to remove the previously mentioned dead spots, and improve circulation
) Glue all the seams with silicone (3M - Blue tube). Circulation can be
enhanced by gluing a partition down the middle of the tank making a raceway
arrangement. Best yields are obtained with a good food circulation, animal
distribution, and strong aeration. This next step is the hardest to explain
without pictures, You need to make six or eight (depending on the length
of your tank) air lift tubes. These are simply 1 inch thin wall PVC, cut
at 45 degrees on the bottom, with a 90 degree elbow on top. The water level
should reach the middle of the elbow, with the tube touching the bottom
of the tank, 45 degree cut down. Drill a hole in the 90 degree fitting
so you can feed an airline 3/4 of the way down the tube. Glue these tubes
to the center divide so that the 90 degree elbows all face the same direction
at a 45 degree angle to the divider. Your creating a mechanism to make
a constant flow of water in a clockwise or counter clockwise direction
(I dont think it matters which).
Here is where I should bring up the subject of aeration, avoid the
temptation to put in wood airstones to increase flow and aeration. Yes
they make beautifully fine bubbles and you can get excellent upflow with
them. But its these same fine bubbles that will wreak havoc with your artemia.
Artemia cannot tolerate fine bubbles since they can lodge in the swimming
appendages and kill the little buggers. Artemia can actually ingest fine
air bubbles which will wipe them out (I dont think you can use Gas-X for
I havent had much problem with water quality, so filtration really
isnt necessary on the small scale that were on. Filtration can be included
if You feel so inclined, but it will require a screened overflow to a sump
or cartridge filter.
Moderate aeration with coarse or no airstones, good water quality,
and generally clean conditions are all important for raising high densities
of adult brine shrimp. Since the artemia feed constantly, faster growth
rates and better survival is achieved by multiple or continuous feeding
over a 24 hour period. Best growth rates are achieved at 25-30 degrees
C with salinities of 30-50 ppt and LOW light levels. Remember, artemia
are drawn to strong light, so if you install that 175 watt metal halide
lamp you had leftover from the reef tank, the little buggers are going
to increase their swimming activity and have greater energy expenditure,
resulting in slower growth rates. In low light the artemia will spread
out in the water column, swimming slowly and achieving more efficient food
Being a low volume operation, water quality can deteriorate rapidly,
especially as biomass increases (I mean, thats the whole idea right?).
The problem usually occurs because of over feeding, which leads to fouling
and low oxygen levels. There is a fine line between optimal feeding levels
and wiping out our tank, especially when using non-living foods. To help
overcome this problem, you need to take care of your artemia tank as much
as you pay attention to your aquarium. Here is what you do: Clean the bottom
every couple of days. You do this by turning off the air, letting the tank
settle, and using that handy flashlight again (I find this works best when
done at night) By now we know what our little buddies are going to do.
Meanwhile siphon the crap off the bottom of the tank, remember, these guys
are going to molt 15 times before becoming adults. (unless you have three
hands, prop the flashlight on something). About a 20% water change per
week is adequate.
My artemia just crapout and die - several causes, there could
be insufficient aeration leading to asphyxiation, or you couldnt resist
and used that damned wooden airstone I told you not to use. Or - theyre
starving to death. The health status can be checked by looking at how theyre
swimming, shine your flashlight into the tank, and they all should rapidly
concentrate at the source, this is good. However, slow dispersed swimming
indicates things are going to hell quick. If you have access to a microscope
you can examine their digestive track, which should be full of food (assuming
youve been feeding them, and you have right?) If the swimming appendages
and mouth region are clean, this is good. If they are covered with food
particles, this is bad. This condition could be due to the nature of the
food or the physiological condition of the animals.
Slow growth - Temperature is too low, pH imbalance, salinity
is off, inadequate food or lousy food quality.
Your artemia can be stored for future use in several different ways,
adult artemia will survive for several days in the refrigerator (if your
wife will let you, mine wont) If you refrigerate them, be sure to warm
them up and give them one last feeding before you feed your fish. this
will restore their nutritional quality, after all, theyve been starving
for the past couple of days. You can also freeze them, nope, fraid this
kills them. An ice cube tray works perfect for this (here we go with the
wife again, I cant do nuthin) Be sure to freeze them in 7-8 ppt saltwater
for best results. Freezing is neat because all you have to do is toss an
artemia cube into the tank, and you have a nifty time release food supply.
You have to be careful not to over feed here, they float to the bottom
and decompose quick, and you can bomb your tank rather rapidly.
Decapsulating Brine Shrimp Cysts
Having had several questions on how and why this is done, I have decided
to include this procedure at the end of this FAQ. It is an involved process
and not many people will choose to perform it, but it is good information
to have in case you get a wild hair some day, or just want to impress your
Separating nauplii from their shells may be desirable for several reasons.
Cyst shells are indigestible and can lodge in the gut of predators causing
fatal obstructions, and the shells have been speculated to be a source
of heavy bacterial contamination. While in all my years of messing with
these guys, I have never heard of anyone having problems with either of
these two scenarios, quite a few commercial aquaculture ventures go to
the trouble of decapsulation. Decapsulation is accomplished in four steps:
re-hydrating the cysts, treating with the decapsulation solution, washing
and deactivating the residual chlorine, and the hatching of the embryos.
Dry cysts have a dimple in their shell which makes it hard to remove
the complete inner membrane. For this reason, the cysts are first hydrated
into a spherical shape. The cysts should be re-hydrated in soft or distilled
fresh water at 25 degrees C for 60-90 minutes. The lower the temperature,
the longer it takes to re-hydrate them. But, no matter what the temperature,
never leave them longer than 2 hours, as this decreases the percentage
of decapsulated cysts and lowers the hatch rate. Hydration should be done
in a container identical to the one used for hatching regular cysts for
the same reasons of circulation and aeration. Cysts should be filtered
on a 100-125 micron collection screen and rinsed, but this step may be
missed if you dont have the screen. It is best to decapsulate the hydrated
cysts immediately, but they can be refrigerated for several hours if needed.
During the hydrating process, you need to prepare your chlorine solution.
Either household liquid bleach or powdered pool chlorine is mixed with
In preparation for decapsulation the cysts are placed in a pre-cooled
buffered solution, 4 degrees C and about pH 10, consisting of 0.33 ml of
40% sodium hydroxide (NaOH) and 4.67 ml of sea water per gram of cysts
( you may have a hard time finding NaOH, most pharmacies should have it
though, I got some from work so I havent really looked much). The buffer
solution is prepared by dissolving 40 grams of sodium hydroxide in 60 ml
of fresh water. Decapsulation will begin when you add 10 ml of liquid bleach
to the buffer solution. You will need to have a thermometer in the brew,
because the chemical reaction taking place gives off heat. It is important
to keep the solution between 20 and 30 degrees C. Starting with pre-cooled
buffered seawater makes it easier to keep the reaction in the right temperature
range. If you need to, an ice cube can be added to help drop the temp.
A second method is to add 0.70 grams of dry pool chlorine powder per
gram of cysts. In this case the buffer is sodium carbonate consisting of
0.68 grams sodium carbonate in 13.5 ml water. It is easier to split the
water in two equal parts, add the required amount of chlorine to the first
part, and the sodium carbonate to the second. Allow them to dissolve and
react, which will cause a precipitate. Pre-cool the two solutions, and
mix them together, then add the hydrated cysts. During decapsulation, stir
the brew continuously to minimize foam formation, and to dissipate heat.
Note the color of the solution, it will change from a dark brown to grey,
to white, and then to a bright orange. This reaction usually takes 2-4
minutes. With the calcium hypochlorite solution, the cysts will change
only to gray, and will take about 4-7 minutes.
The cysts can be filtered from the solution as soon as the membranes
have dissolved as indicated by the color (bright orange or grey). The chlorine
should be washed off the cysts by rinsing with fresh water or salt water
until you cant smell the chlorine anymore. The residual chlorine attaches
itself to the decapsulated eggs, and has to be neutralized. Do this by
washing the cysts in a 0.1% sodium thiosulfate (0.1 gram sodium thiosulfate
in 99.9 grams water) for one minute. An alternative method uses acetic
acid (1 part 5% vinegar to 7 parts water). The first method works better,
but the second method is easier as everyone has the materials in their
kitchen. The cysts are then re-washed with fresh or sale water a placed
into the hatching container, and hatched as normal artemia. The decapsulated
cysts can be hatched immediately, or stored in the refrigerator for up
to 7 days before hatching. For long term storage, like the expensive stuff
you can buy, the cysts need to be dehydrated.
Dehydration of the decapsulated cysts is done by transferring your
one gram of decapsulated cysts into a saturated brine solution of 330 grams
salt to 1 liter water. Aerate this for 18 hours, replacing the solution
every 2 hours. The cysts are releasing their water through osmosis in the
solution, so it is important to keep the salt concentration high. After
18 hours, the cysts have lost about 80% of their cellular water, stop the
air flow and let everything settle, then filter the cysts out. These cysts
can then be placed in a container and topped off with fresh brine solution.
seal the container and store it in the refrigerator or freezer. Cysts with
16-20% cellular water can be stored for a few months without a decrease
in hatching rate. For a longer term storage, you have to reduce the cellular
water content to less than 10%
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