Brine shrimp also known as sea monkeys or artemia salina are a type of small crustacean that are commonly used as live food for feeding fish and other aquatic animals. Their eggs, referred to as cysts, are an essential part of the aquarium hobby and are hatched by the millions each day. But one question that often puzzles aquarists is – do brine shrimp eggs float or sink when you first add them to saltwater to begin the hatching process?
The answer is…it depends! Brine shrimp eggs go through several stages during the hatching process and their buoyancy changes along the way. Here is a complete step-by-step guide on what happens to brine shrimp cysts from start to finish:
The Stages of Brine Shrimp Eggs
Dry Cysts Stage
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When brine shrimp eggs are in their dry, dormant cyst state they initially float when first added to saltwater. The cysts contain an oil droplet which makes them buoyant.
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Dry cysts are dark brown in color and around 200-300 microns in diameter when viewed under a microscope.
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They will bob around the surface of the saltwater in the hatchery due to the internal oil droplet providing natural flotation.
Activated Cysts Stage
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After 6-12 hours of being submerged and hydrating in the saltwater, the outer shell of the brine shrimp eggs begins to soften and sink.
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During this activated stage, the cysts turn from dark brown to a lighter tan color as the embryo’s metabolism speeds up to prepare for hatching.
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The specific gravity of the cyst increases as water penetrates the shell, causing it to lose buoyancy and sink.
Hatched Nauplii Stage
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Following approximately 18-36 hours of incubation, the brine shrimp fully emerge from their cyst shells as free-swimming nauplii.
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The hatched nauplii will float up in the water column because they are positively buoyant.
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Newly hatched brine shrimp are around 400-500 microns in size and must undergo several molts as they mature over 2-3 weeks.
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After multiple instar stages and molts, they reach adulthood as grown brine shrimp.
Tips for Hatching Brine Shrimp Eggs
Hatching brine shrimp cysts does require some precision to achieve high hatch rates. Here are some best practices:
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Purchase high-quality cysts without white spots which indicate dead eggs. Brown cysts stored properly in refrigeration tend to hatch better.
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Use marine salt to create saltwater that is 25 ppt salinity. Too high or low will inhibit hatching.
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Maintain pH above 8.0 and temperature of 82°F for ideal hatching conditions.
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Vigorous aeration is critical to keep the cysts suspended during incubation.
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Lighting triggers the hatching response in the brine shrimp embryos.
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Rinse the nauplii after hatching to remove debris before feeding them to fish.
What To Do If Your Brine Shrimp Eggs Are Not Hatching
Sometimes brine shrimp fail to hatch despite our best efforts. Here are some troubleshooting tips if your cysts refuse to hatch:
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Verify the saltwater salinity is exactly 25 ppt. Too high or low will prevent hatching.
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Test and adjust pH to 8.0-8.3 range if too acidic. Low pH inhibits hatching.
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Increase temperature to 82°F if too cold. Cool water will stall the hatch.
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Use strong aeration to suspend the eggs and keep them tumbling.
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Add a light source over the hatchery if incubating in total darkness.
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Try a fresh batch of eggs if old and storage time was too long.
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Be patient and allow up to 48 hours for older eggs to hatch since they are slower.
Harvesting the Newly Hatched Brine Shrimp
Once the brine shrimp have begun hatching, it’s time to harvest them to feed your fish! Here are a few tips:
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Turn off the air pump and let the nauplii settle for 5-10 minutes before harvesting. This allows separation from the floating cyst shells.
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Use airline tubing as a siphon to suck up the nauplii collecting at the bottom of the hatchery.
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Drain the nauplii out slowly through a valve if your hatchery cone has one.
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Gently scoop them out with a small fine mesh aquarium net. Avoid damaging the delicate nauplii.
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Give the nauplii a quick rinse in saltwater before feeding them to your fish.
Storing Extra Brine Shrimp Nauplii
Having leftover brine shrimp after feeding your fish? Here’s how to store them:
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Refrigerate in clean saltwater for up to 2 days for short term storage. Change the water daily.
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For longer term storage up to 2 weeks, freeze brine shrimp in ice cube trays with a bit of saltwater.
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Thaw frozen brine shrimp by moving to the refrigerator overnight before feeding out.
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Previously frozen nauplii may take 1-2 hours to regain movement and color once defrosted.
Proper storage keeps freshly hatched brine shrimp nauplii viable for extended periods until you are ready to feed them to your fish and coral!
Enriching Brine Shrimp for Improved Nutrition
To further boost the nutritional value of brine shrimp:
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Soak in vitamin solutions like Selcon to enrich with essential fatty acids.
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Add seaweed extract like Phytoplankton or marine algae to the water to enhance pigmentation.
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Feed the brine shrimp enrichment formulas like dry foods before harvesting.
Enriching brine shrimp helps provide vitamins, minerals, carotenoids and more to raise vibrant, healthy fish.
Hopefully this guide has shed some light on the question of whether brine shrimp eggs float or sink during the hatching process. While it may seem complicated, following the best practices outlined here will help you achieve great hatch rates. Pay close attention to the stages of the eggs, dial in optimal saltwater conditions, and use proper harvesting techniques. Your fish will be thriving on these freshly hatched brine shrimp in no time!
Instructions for Hatching Brine Shrimp
This page has the best and easiest-to-follow brine shrimp hatching instructions on the web. You can use a Hatchery Dish or a regular cone-shaped container (Imhoff cone or inverted bottle) to hatch the eggs.
Before we begin, you need to start with viable, properly stored eggs. All brine shrimp eggs need to be stored as follows:
- in a tightly sealed container;
- free from moisture; and
- in a cool environment at or below 40°F. (Refrigeration is ideal for short term storage, i. e. , less than three to four weeks. To store eggs for a long time, they should be kept at or below freezing. ) .
When you get your eggs, we suggest dividing them into two groups: one should be kept in the fridge in a container with a tight lid for three to four weeks, and the other should be kept in the freezer in the same container with a tight lid for longer. Keep in mind that freezing can lower metabolic activity and delay hatch-out. We suggest taking the egg out of the freezer one day before you want to use it so that the embryos have time to get used to the temperature.
The above storage guidelines apply to all brine shrimp eggs, whether in opened or unopened tins.
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If you want to get the best results from conical hatching containers like our 2-Liter standing cone, an Imhoff cone, or an upside-down soda bottle, follow these steps:
- For most situations, a 25 parts per thousand (ppt) salt solution is best when making your hatching solution. This equates to around 1. 018 specific gravity as measured with a hydrometer. If you don’t have a hydrometer, you can get this salinity by mixing about 1 and a half tablespoons of salt with one quart (about a liter) of water. Be sure to use non iodized salt.
- pH: Proper pH can be important in hatching brine shrimp. A starting pH of 8. 0 or higher is recommended. Some places have water with a pH below 7. To those places, you can add 1/2 teaspoon of Epson salt or magnesium sulfate per quart of hatching solution.
- Temperature: The best water temperature for a full hatch that lasts 24 hours is between 26 and 28°C (80 to 82°F). Lower temperatures will cause hatching to take longer and not work as well. Do not exceed 86° (30°C). Do not put an immersion heater right into the container where the eggs are hatching! An immersion bath is better for keeping the temperatures stable. If the conditions are right, an incandescent bulb placed above the hatching cone can also provide enough heat.
- Light: During the first few hours of incubation, the embryo needs to be lit up in order to start the hatching process. Keeping a light on during the whole incubation period is suggested for the best hatch results and, as we already said, to keep the temperature stable.
- Continuous aeration is needed to keep cysts in suspension and make sure there is enough oxygen for the cysts to hatch. During the incubation, there should be at least 3 parts per million of dissolved oxygen. Strong air flow shouldn’t hurt or damage the cysts or nauplii of brine shrimp. A rigid air tube is the best way to get air to the bottom of the cone and keep eggs that haven’t hatched from falling to the bottom. We do not recommend an airstone.
- For the best hatching rates, stocking density should be 1 gram per liter or quart, which is about 1/2 teaspoon of cysts per quart (or liter). A higher stocking density will lower the number of eggs that hatch and make it harder to tell the difference between hatched nauplii and eggs that haven’t hatched yet.
- Hatching Cone: Flat-bottom hatching vessels should be avoided. Containers with cone or “V” bottoms work best to keep the cysts floating while they hatch. When not in use, make sure to wash the hatching cone well with a mild chlorine solution, rinse it, and let it dry naturally. Avoid soap. Soap will leave a thin film that will foam when the eggs hatch and leave the cysts floating above the water.
- Incubation Period: Generally, the optimum incubation time is 24 hours. If an egg has been stored properly for more than two to three months, it may need more time to hatch—up to thirty to sixty hours. Oftentimes, eggs will hatch in as few as 18 hours. If you want smaller nauplii (Instar I), you should wait 18 hours before harvesting them. After that time, you can get Instar I (first stage) nauplii before they change into Instar II.
Brine shrimp egg is sometimes very buoyant. To get the most eggs to hatch, it can help to swirl the water in the hatching container with your finger a few times during the first four to six hours of incubation. This will knock down any eggs that are sitting on the side of the container above the water line. After about 6 hours, the eggs are usually well-hydrated and will stay in the water column.
The following steps will achieve optimum brine shrimp hatch rates.
- Set up: Put a hatching cone or other similar-shaped container in a well-lit area. The cone should be partly see-through so that it is easy to harvest and let light through.
- To add water, fill the cone with water and set the salinity to 25 ppt. Optimum hatching temperature is 82°F (28°C).
- Add Cysts: Put in 1 gram of cysts per liter.
- Aerate: Provide adequate aeration to keep cysts in suspension.
- Hatch: Eggs should hatch in 18 to 36 hours, depending on the temperature of the water.
- Harvest: Once the brine shrimp have hatched, turn off the oxygen and wait a few minutes for the shells and baby brine shrimp (called nauplii) to separate. New nauplii will either fall to the bottom of the cone or move toward a light source. The shells will float to the top. If there is a valve on the bottom of the cone, the nauplii can be gently drained through it or sucked out of the bottom with a length of air tubing.
- To sum up, the warm temperatures during incubation and the chemicals in the hatching medium make it perfect for a bacteria bloom. Before you feed the baby brine shrimp to your fish, you should rinse them in clean fresh or salt water through a fine mesh net or sieve.
- Clean Equipment: Tanks and equipment used to hatch brine shrimp should be cleaned and sanitized regularly.
Flat-bottom hatching vessels should be avoided. Cone or “V” bottomed containers are best to insure that the cysts remain in suspension during hatching. When not in use, make sure to wash the hatching cone well with a mild chlorine solution, rinse it, and let it dry naturally. Avoid soap. Soap will leave a thin film that will foam when the eggs hatch and leave the cysts floating above the water.
Generally, the optimum incubation time is 24 hours. If an egg has been stored properly for more than two to three months, it may need more time to hatch—up to thirty to sixty hours. Oftentimes, eggs will hatch in as few as 18 hours. If you want smaller nauplii (Instar I), you should wait 18 hours before harvesting them. After that time, you can get Instar I (first stage) nauplii before they change into Instar II.
How to Hatch Brine Shrimp Eggs with NO Equipment | NO Air Pump Easy Setup
FAQ
Should brine shrimp eggs sink or float?
Why are brine shrimp eggs sinking?
How to tell if your brine shrimp hatched?
Why do brine shrimp eggs not hatch?
How to hatch brine shrimp eggs?
To hatch brine shrimp eggs, fill a well-lit, semi-translucent cone or similarly shaped vessel with one liter of water and add 11/2 tablespoons of salt. The optimum hatching temperature is 82°F (28°C). Place the cone in a well-lit area for optimal hatching rates.
How do you hatch brine shrimp?
Brine shrimp are super easy to hatch out. You could just hatch shrimp in a cup of salty water with a bubbler on a shelf. What makes a great hatchery vs a crappy one is how well it separates the shrimp egg shells from the hatched shrimp. The egg shells are not digestible. You don’t want to feed those to your fish.
How many brine shrimp eggs per liter of water?
It is generally advised to follow the manufacturer’s instructions regarding the egg-to-water ratio. However, a commonly used guideline is to add approximately half a teaspoon of brine shrimp eggs per liter of water. After adding the brine shrimp eggs to the hatching container, it is crucial to allow them to incubate properly.
Does brine shrimp need saline water?
Here’s the catch – brine shrimp eggs need saline water to start hatching. A simple solution (pun intended) is to mix 1.5 tablespoons of non-iodized salt per quart of water. Voila! You just made yourself some shrimp-ready water. As an eager shrimp daddy (or momma), you’ll probably want to keep a close eye on your hatchery.