Brine Shrimp (Artemia Salina) are saltwater organisms which are quite popular because of their great economic importance in the aquaculture industry.
The brine shrimp is one of the typical filter-feeding plankton. They are small members of the fairy shrimp order Anostraca, they are characterized by their tiny structure, size and unique features essential for adaptability to various living conditions and habitats. Brine shrimp are majorly utilized as live-feed for fishes and other freshwater organisms due to its rich protein content.
In this post, I will enlighten you on all you need to know about the brine shrimp popularly known as Artemia and how you can culture them for use in the hatchery.
Description of the Brine Shrimp
Brine Shrimp (Artemia Salina) are relatively tiny organisms commonly found in isolated habitats, namely salt lakes and water bodies like the renowned Great Salt Lake (Utah), Rocky Coast south of San Francisco and the Caspian sea.
Other species can be equally found in many other water bodies with high or moderate salt content.
Appearance of the Brine Shrimp
This organism is an arthropod with a distinct segmented body of broad leaf-like appendages called phyllopodia that greatly increase the apparent size of the animal and they often beat in a regular rhythm.
The body of the Brine shrimp is divided into head, thorax and abdomen. The head consists of one pretomial and five metameric segment which bears the compound eyes set on a flexible stalk, the mouthparts and antennas.
In addition, the thorax has eleven segments each bearing a pair of swimming legs while the abdomen consists of eight segments. The anterior two abdominal segments are referred to as the genital segments.
A thin flexible chitin (exoskeleton) covers the body to which muscles are attached internally; the molting process enable the brine shrimp to shed away its old exoskeleton allowing a new stronger exoskeleton to form.
Habitat / Ecology of the Brine Shrimp
Brine shrimp have a notable resistance to changes and are able to live and thrive successfully in a wide range of water salinity. All containing some sea salt content ranging from brackish water (2.9 – 3.5 %) to the Great salt lake (25 – 35 %) and they can tolerate up to a 50% salt concentration which is almost saturated. Some are found in different salt swamps just inland of the dunes of the seashore, but never in the ocean itself because of the presence of many predators. They are found in about 500 natural salt lakes and man-made salterns scattered throughout the tropical and temperate climatic zones of the world.
Although brine shrimp can thrive well in natural saltwater habitats, they cannot move from one saline biotope to another through the seas as they depend on their physiological adaptations to high salinity to avoid predation and competition with other similar filter-feeders. Its physiological adaptations to high salinity provides a very efficient and effective ecological defence against predation.
Brine shrimp possess the following adaptive features:
- A very efficient osmoregulatory system
- The ability to synthesise very efficient respiratory pigments to cope with the low oxygen levels witnessed at high salinities.
- The ability to produce dormant cysts within a very short period when environmental conditions endanger the survival of the species.
Behaviour of the Brine Shrimp
A distinct feature of the brine shrimp is the up-side down swimming as compared to the majority of aquatic animals. This is a result of positive phototaxis, which means the brine shrimp is attracted to the light, and in nature it is found with its appendages pointed upward, because the sun is the natural light source. Also, because the brine shrimp are attracted to the light, they tend to rise toward the surface during the day and sink again at night.
The same rhythmic movement of the phyllopodia that moves their food anteriorly is the brine shrimp’s means of locomotion. They beat their appendages to propel themselves through the water towards the food in sight, without much regard for the rest of the environment.
They collect food by either filtering little particles with fine spines on the legs as they swim or by grazing on bottom mud and scraping algae off rocks with fast movements of their appendages. After the algae is captured, a feeding current moves it anteriorly to the mouthparts through a central median food groove using the regular rhythm of the phyllopodia. They feed on some other organisms in the water bodies: yeast and bacteria and also plant & animal feeds like wheat flour, soybean powder, egg yolk if available.
The Brine Shrimp is efficiently adapted for life in a habitat of a wide range of salt concentration. Their gills aid them to deal with high salt content by absorbing and excreting ions when necessary.
Life Cycle of the Brine Shrimp
According to the researches, Brine shrimp reach sexual maturity within 18 – 21 days after hatching and reproduce in two ways.
- Brine Shrimp reproduces when a male clamps on a female with his large second antannae and fertilizes her eggs, thereby leading to production of diploid zygotes. Afterwards, the female lays the eggs in a brood sac in the water.
- Reproduction without fertilization (parthenogesis) is also common among brine shrimp where a female lays unfertilised eggs that will develop into female offsprings.
The eggs will only hatch if environmental conditions are right. The ideal temperature must be around 30 degree Celsius (~86F), water supply plentiful and salt concentration not too high. If these conditions are not fulfilled, fertilised eggs are deposited as cysts and remain dried and encased in a thick shell until they are ready to develop.
Note: The eggs will not hatch if SG is more than 1.09 and the temperature less than 10C.
The cysts may be immersed in water several times before hatching. Upon immersion in seawater, the bioconcave-shaped cysts hydrate, become spherical, and the embryo resumes its active metabolism.
The cyst’s outer membrane cracks and the embryo emerges after a 20-hour interval. The embryo hangs underneath the empty shell and the development of the nauplius (larva) is completed. Afterwards, the hatching membrane ruptures and a free-swimming nauplius is born.
Studies show that prior to hydration, the cysts of Artemia salina are cup-shaped with a diameter of approximately 0.18 mm. Upon immersion in sea water, the cysts slightly increase in diameter to 0.19 mm and assume a spherical shape. Hatching begins with the splitting of the surface coat. The split runs along a straight line, approximately one-half the circumference of the cyst.
Once completely emerged from the cyst, the nauplius begins a series of beating movements which rupture the hatching membrane, allowing the nauplius to swim free.
Brine Shrimp Larval Stages
The first larval stage is characterised by a distinct brownish-orange colour, a red nauplius eye in the head region and three pairs of appendages i.e. the first antennae (sensorial function), the second antennae (locomotory + filter-feeding function) and finally: the mandibles (food intake function). The ventral side is covered by a large labrum (food intake).
The digestive tract of the nauplius is not in contact yet with the external medium. Therefore, the larva depends on its yolk reserves as the sole food source at this stage. As they use this yolk sac, the
hatch brine lose nutritional value and caloric value.
After 8 – 12 hours, it molts into the 2nd larval stage. At this stage, algae and bacteria are filtered and ingested into the digestive tract by the animal.
Note: When not fed, Artemia larvae will die during the third or fourth instar stage.
The larvae undergo about 15 diverse molts to grow and differentiate. Paired lobular appendages appear in the trunk region and differentiates into thoracopods. On the both sides of the larva lateral complex eyes can be seen developing.
From the 10th larval stage, morphological and functional changes starts occurring. In males their antennae grows and develop into hooked graspers while the female antennae degenerates into sensorial appendages.
Furthermore, the thoracopods are now differentiated into three active functional parts: the telopodites and endopodites (locomotory and filter-feeding) and membranous expodites or gills for respiration and other activities.
Facts to note: Brine shrimp are capable of reproducing 300 new nauplii every 4 days. As they grow and develop, they undergo various stages and each stage is separated form the next by a molt.
Brine Shrimp, Water Parameters and Salt
It is important to ensure that the water in the hatching mechanism can actually facilitate proper hatching of the brine shrimp eggs.
Maintain the following water parameters:
- Water temperature: 5 to 27.5°C (80 – 82°F)
- pH: Not lower than 8
- Stocking Density: 1 gram of brine shrimp eggs per 1 litre of water.
- Salt: Instant Oceans, Epsom salt, Aquarium rock salt, even Kosher salt.
What Salt to Use?
You can use some Instant Oceans, Epsom salt or aquarium rock salt and baking soda to get the right salt concentration needed in the hatchery, anything slightly above the average salt concentration (25ppt = SG- 1.018) is good.
Note: Actually, there is no need to use Instant Oceans when you can have almost the same result with the cheaper ones. The point is that Brine shrimp will not live long enough to feel the difference anyway.
Calculation Tip: If you do not have hydrometer, you need to add approximately 2 tablespoons of noniodized salt in one quart (roughly, one liter) of water. The exact amount of salt is not critical.
Hatching Brine Shrimp. DIY Setup
One of the best food for fishes, shrimp, crabs and other aquatic animals is definitely freshly hatched brine shrimp. These are very rich in protein and fatty acids, which is quite essential in promoting growth and development. Here, I am going to provide you with a detailed and comprehensive guide on how you can hatch and grow fresh brine shrimp for your home aquarium.
You can easily opt for a DIY hatching setup using a funnel-shaped container considering how expensive hatcheries can be. Although they are not very convenient and effective as brine shrimp hatchery kit, or hatcheries (links to check the price on Amazon) available at the pet store but they are easy to set up and gets the job done.
- A large soft drink plastic container (bottle).
- Air pump with airline tubing and rigid tubing.
- Non-Iodized Salt (Aquarium salt or Epsom salt or Instant Ocean Sea Salt, etc.).
- Baking soda.
- Brine shrimp eggs (or like this one).
- Light source (for example, Desk lamp with Incandescent or halogen light bulb that produces heat).
Basic DIY Setup
- Take a large (1.5 – 2 litres) bottle and cut 1/3 of the bottle from the bottom.
- Fill the bottom part with something heavy (gravel, sand, etc), to make it more stable.
- Reverse the top part and place into the bottom part of the bottle.
- Add an airline for filtration tight to the bottom at the centre.
Important: If you misplace the airline, some cysts will not be affected by the aeration and will stay at the bottom. You can use the rigid airlinetubing if you have one or jam your airline in the center of the cap.
- Add a gang valve to control airflow.
Important: The airflow should be strong enough to keep all cysts suspended. However, not so strong as to allow it to bubble over.
- Add dechlorinated water (Just age you water prior to use. Chlorine will usually evaporate out of water within 24 hours.).
Note: Lots of people say that this step is not necessary. Well, it can be so if you have soft water. However, if you have hard water, brine shrimp eggs may not hatch in water that contains chloramines or the successful rate will be low.
- Add Salt and Brine shrimp eggs.
- Do not forget to cover the top of the bottle. That way the bubbles over spray will not end up on your table and lamp. In addition, this also helps to keep the water warm and reduce evaporation rate.
Step 1: Hydration Brine shrimp
- Set your hatchery in a room with temperature between 25 – 30°C (77 – 86°F) or use the lamp to heat.
- Position your light source about 6 – 8 inches (15 – 20 cm) away from the container.
- Fill up the hatchery with about 1 litre of clean tap water.
- Add the salts: add 2 tablespoons of rock salt (non iodised salt) and ¼ teaspoon of Epsom salt and 2 tablespoons of any commercially available artificial seawater mix.
- Add ¼ teaspoon baking soda, unless you are quite certain the water pH is greater than 8.0.
- Ensure you place airline inside the container so that the opening touches the bottom.
- Connect the other end to a small aquarium air pump and adjust the airflow until you get a steady stream of bubbles that begin at the bottom and equally rise to the top.
- Add 1 teaspoon of healthy eggs (cysts).
- Allow the eggs to soak up water for ab hour before proceeding.
- Cover the hatchery to prevent water avaporation.
Step 2: Incubation Brine shrimp
The next step is incubating the eggs till they hatch successfully.
- Continue to aerate and illuminate the hatchery.
- Use your finger or a spoon to plunge the ring of eggs, which tend to base at the surface back into the water.
- You should allow the eggs to incubate for 24 – 36 hours to hatch.
Note: It depends on the temperature. The higher the temperature the faster Brine shrimp hatch. However, do not exceed 30º C (86º F), or the young brine shrimp may be damaged.
- When the Brine shrimp hatch, the water will change color to orange.
- Disconnect the airline fixed to the end of the pump and move the light source to the very bottom of the container. The essence of this is simply because the brine shrimp nauplii (larvae) are positively phototactic hence they will always move towards the light source.
Tip: If the lamp is too big/bright and you cannot manipulate the light – just cover the top halve of the bottle.
- Wait 5 to 10 minutes for the baby brine shrimp to swim to the bottom of the container. The shells of hatched eggs will float, unhatched eggs will settle to the bottom, and the young shrimp (nauplii) concentrate in the light.
- Using the airline, you are advised to siphon only the orange coloured baby brine shrimp from the bottom of the cone into your designated shrimp net, which should suspend in a glass of water to prevent damage to the nauplii. However, do not siphon hatched shells, which tend to float at the surface.
- Important: Quickly and gently rinse the baby brine shrimp with clean tap water at your sink. You can use a coffee filter to rinse it. We do that to avoid adding any unwanted salinity to our tanks. This is especially important if you have a freshwater tank.
- Feed each aquarium with the freshly hatched baby shrimp. Do not deposit too much brine shrimp all at once rather feed as much as your fish can consume in a couple hours. Do not overfeed!
- Tip: You can enrich Brine shrimp with astaxanthin to improve coloration of your fish, shrimp or crabs.
Step 4: Reusing the Hatching Water
- We can safely reuse the hatching water 2 – 3 times more (but … why!).
- Remove eggshells.
- Top up with freshwater, if you forgot to cover the container and some of the water evaporated.
Step 5: Cleaning
Clean up the hatching equipment to be used for the next hatching process.
- Scrub the container with a sponge and properly diluted household bleach
- Rinse it thoroughly to remove all dirt.
- Tightly seal the egg container to prevent moist air from coming in contact with the egg cysts.
- Store in the refrigerator until the next usage.
Brine Shrimp and Aquaculture
The nauplii of the brine shrimp is commonly used in the culture of fishes, crabs, dwarf shrimp (Neocaridina, Caridina, etc.) and other freshwater organisms. The incubation of brine shrimp cysts in the hatchery results in the release of nauplii that can directly be fed to the larvae of a variety of freshwater organisms.
Note: Dwarf shrimp are scavengers and prefer dead organic matter. So, frozen brine shrimp is your choice.
Brine shrimp are known to have high nutritional value. They have high protein content and are rich in amino acids. They make a bigger prey thus resulting in a better energy balance per hunting effort for predating fishes or shrimp larvae that can ingest them. Brine shrimp is very popular as live feed for ornamental fish in the tropical aquarium industry, it can be frozen, freeze-dried or acid preserved for later use or made into flakes.
If you are into aquaculture and need the least labour-intensive live feed for your baby fishes then the brine shrimp is your best bet. They are nutritious, easy to obtain, hatch and harvest; your fishes will love them totally!
FAQ about brine shrimp hatching
Can I refrigerate brine shrimp?
Yes. They can be refrigerated (not frozen) for several days.
Why are my brine shrimp dying?
They could be overcrowded. If so, divide the culture. There could be insufficient aeration, or you could be using a wooden air stone or other air stone that produces a fine “mist” of bubbles. These small bubbles can clog the shrimp’s feeding system and starve them.
Do brine shrimp need light to hatch?
Actually, brine shrimp do not need light to hatch. We use light to heat the water and manipulate its movement. Some people believe that light can also trigger the hatching mechanism. Personally, I do not think that it plays such a big role.
Do brine shrimp need an air pump?
Yes, brine shrimp need an air pump. We use it to keep the water oxygenated (so brine shrimp will not suffocate). In addition, flowing water prevents them from sticking to the sides of the container.
Do brine shrimp need a heater?
Brine shrimp need a warm temperature. They do not care about the source of the heat. It can be a heater, a table lamp, or anything else.
Can fish eat brine shrimp eggs?
No, fish cannot eat eggs. The eggs cannot be used as fish food because fish cannot digest the tough shells.
Why Won’t My Brine Shrimp Hatch?
There can be many reasons for that, for example:
- The brine shrimp eggs are too old.
- The temperature is too high or low.
- Too low pH.
- Too high salinity level. As I have already said before the eggs will not hatch if SG is more than 1.09.
- They need more time. Sometimes after the freezer, it can take them 36-48 hours to hatch instead of 24 hours.
How can I store Artemia Eggs?
The brine shrimp eggs will remain viable (alive) for at least 10 years when stored in:
- A dry and tightly sealed container.
- A fairly cool place at or below 50°F for a few weeks. (For longer-term storage, put your brine eggs in a freezer).
Nonetheless, keep in mind that old eggs have a greatly reduced hatch rate.