Live Feeds: Artemia
Developed by the Harbor Branch ACTED staff
Live Foods
• Fish larvae must be fed live foods
which have the nutrition and enzymes
(exogenous) they need, before their
own digestive system is formed.
• After the fish has developed its own
digestive system, then weaning to dry
feed can begin.
Live Foods
• The two main live feeds commonly used :
– Rotifers
– Artemia (brine shrimp)
• Other live feeds include:
– Mollusc trochophore larvae
– Ciliates
– Copepods
– Wild plankton
Live Foods
Most commercial hatcheries rely on
rotifers and Artemia, for their ease of
production, cost and reliability.
Rotifers
• Rotifers can be produced using algae,
yeast, or other custom products, or a
combination.
• Rotifer production range from 100 to 10,000
animals per ml.
• Rotifers are usually maintained in larvae
tanks at a density of 5 to 30 per ml of larval
tank water.
Brine Shrimp, Artemia
Photograph by HBOI
Brine Shrimp (Artemia)
• Artemia can be hatched in 17 liter
containers with hatches of 5 to 10 million.
• Artemia are maintained at less than 1 per ml
of culture water.
Brine Shrimp (Artemia)
• Newly hatched brine shrimp have
maximum nutritional value.
• Artemia lose their nutritional value after
10 - 12 hours.
• At this time Artemia begin to feed and
may be enriched with various products
including algae.
• After 24 hours, the enriched Artemia is
fed to larvae.
Brine Shrimp (Artemia)
• Most enrichment products increase the fatty
acid content of the shrimp which is beneficial
to larvae.
• Other beneficial products can be
incorporated into Artemia, including:
– Probiotics
– Medications
Conventional Hatching for Marine Fish
(No de-capsulating)
1. 8 a.m. Disinfect cysts with chlorine and hydrate cysts for 1 hour in freshwater.
2. Chlorinate hatching saltwater, de-chlorinate, and check for residual chlorine.
3. 9 a.m. Drain cysts into net, rinse and add to saltwater. Add de-foamer.
4. Next day 8 a.m. Turn off air and let settle until shells, nauplii and unhatched
cysts are separate, about 15 minutes. Drain unhatched cysts on the floor,
then drain shrimp in net, stopping before the shells begin.
5. Rinse shrimp with salt water, and then put in a bucket of saltwater.
6. Remove as many floating shells as possible with a baster.
7. Feed to larvae.
Hatching for Freshwater Fish
(No de-capsulating)
1. 8 a.m. Add salt to freshwater.
2. Add cysts straight from the can.
3. Next day 8 a.m. Turn off air and let settle until shells, nauplii
and unhatched cysts are separate, about 15 minutes. Drain unhatched
cysts on the floor, then drain shrimp in net, stopping before the shells begin.
4. Rinse shrimp with freshwater.
5. Feed to larvae.
Hatching with De-capsulated cysts
1. 3 p.m. Add de-capsulated cysts to seawater. Add defoamer.
2. Next day 7 a.m. Turn off air and drain immediately
into net and rinse.
3. Feed to larvae.
Advantages of De-capsulating
1.
Cysts must be disinfected with chlorine when using
Artemia for saltwater, to kill bacteria such as Vibrio.
2. Cysts do not need to be hydrated before hatching, saving
time.
3. With no shells, nauplii can hatch quicker with less
expenditure of energy (fat content), increasing their
nutritional value.
Advantages (continued)
4. Hatching time is reduced from the normal 24 hours
to 16 hours at 30˚C (86˚F). Nauplii lose their nutritional
value over time, so the extra 8 hours saved means a nauplii
with higher fat content.
5. Quicker hatching time results in smaller, more uniform-sized
nauplii suitable for the smallest sized larvae.
6. There are no shells or unhatched cysts to separate from the
nauplii. Even unhatched cysts can be eaten by larvae.
Advantages of De-capsulating
7. There are no shells or unhatched cysts accumulating
on the surface of larval tanks. Shells or unhatched cysts
can lodge in the esophagus and gut and kill larvae.
8. Hatching percentage increases compared to conventional
hatching of unde-capsulated cysts.
9. It is cost efficient as the price of Artemia has doubled.
10. As Artemia supply can fluctuate, even poorer grades
(quality) of cysts (such as Grade A or B) can be used.
Disadvantages of De-capsulation
1. De-capsulation requires skilled labor as the window of
de-capsulation is only 2 to 4 minutes. Any errors in following
procedures result in loss of time and cost of Artemia cysts
and chemicals.
2. For large scale hatcheries when several cans must be hatched
every day, following the disinfection / hydration techniques
is more time and cost efficient.
De-capsulating Brine Shrimp
Approximately 275,000 cysts/ gram
produce
200,000 – 250,000 nauplii/ gram
or
90 – 113 million per 1 pound can (454 grams)
Materials For De-capsulating
1. Pre-cool (5ºC) 1 gallon of salt water and 1 gallon of liquid
chlorine (10%) in a refrigerator for at least 2 days.
2. Dissolve 20 grams (1/16 cup) of sodium hydroxide Na(OH)2
beads in 30 ml (1/8 cup) of freshwater. Caution mixture is
very hot and can burn skin. Do not inhale fumes!
3. Dissolve 1/4 cup of sodium thiosulfate in a 1 liter beaker of
freshwater.
4. Prepare 4 gallons of brine solution (5 lbs. of crystal salt
dissolved in 5 gallon capacity bucket of freshwater).
5. 1 pound can of Brine Shrimp cysts.
Photograph by HBOI
Photograph by HBOI
Method For De-capsulating
1. Aerate cysts for 1 hour in 15 liters of freshwater
in a brine shrimp net suspended in a hatching cone.
2. Rinse cysts briefly in freshwater.
3. Add the Na(OH)2 solution to 2 liters of chilled salt water.
Discard remaining salt water.
Photograph by HBOI
Method For De-capsulating
4. Add cysts to empty clean cone.
5. Add the 2 liters of salt water mixture. Aerate vigorously.
6. Add 2 liters of chilled bleach to cone.
7. After 2 - 4 minutes, cysts will turn bright orange.
Photograph by HBOI
Photograph by HBOI
Photograph by HBOI
Photograph by HBOI
Photograph by HBOI
Photograph by HBOI
Methods (continued)
8. Add 1 liter of sodium thiosulfate solution and 15 seconds.
9. Turn of the air, drain, rinse with water in a brine shrimp net.
10. Add 2 liters of brine solution to a clean cone. Add cysts and
rinse net with more brine and fill up to the line for the required
number of cups. For example, the number of cups (18) times 200 m
= 3.6 liters water and cysts.
Photograph by HBOI
Method (continued)
12. Aerate slowly for 18 hours.
13. With continued aeration, drain cysts into
16 to 24 (average 18) - 200 ml containers
14. Refrigerate for up to 2 weeks.
Photograph by HBOI
Photograph by HBOI
Photograph by HBOI
Photograph by HBOI
Photograph by HBOI
De-capsulation costs
per pound can
Liquid chlorine
Sodium hydroxide
Sodium thiosufate
Labor time
Less than $2.00
Less than $0.25
Less than $0.25
Less than 30 minutes