The incredible amount of energy packed into brine shrimp makes them the single most important food item in the worldwide tropical fish industry. Without them, we likely would not have the aquaculture industry that we have today. Almost every fish farm and nearly every home fish breeder uses newly hatched brine shrimp to help get their larval fish to a good start. Newly hatched brine shrimp are often the difference between success and failure with raising fish larvae, known in the aquarium hobby as “fry.”
While some aquarists inexplicably dispute their usefulness, the simple fact is that newly hatched brine shrimp have been used successfully by many generations of fish breeders for the past 80 years. The aquaculture industry uses tons of brine shrimp eggs every year. This would be a waste of time and money if it didn’t work. The fact is that feeding newly hatched brine shrimp to fish works.
Brine shrimp eggs are actually cysts. These cysts are an amazing adaptation to a harsh environment. They can withstand years of high heat, desiccation and freezing cold. When the waters return, they burst forth into life within a few hours of being rehydrated. About 80 years ago, aquarists began gathering, drying and storing them in containers until needed. These humble beginnings evolved into the brine shrimp industry aquarists know today.
When the cysts become wet, they begin to swell with water. After about 18 to 24 hours at 78 degrees Fahrenheit, they begin to hatch. Larval shrimp look nothing like adults and are called nauplii. They have a single eye, no mouth and no anus; so they do not eat and cannot process food. But they are packed with energy: proteins, highly unsaturated fatty acids, enzymes and more. All of these just happen to be what larval fish need to help them off to a good start.
During the first 12 or so hours of life (called Instar 1), nauplii use this stored energy. They are attracted to light, so they begin swimming near the surface of the water and preparing for their first molt. Immediately after the first molt, the nauplii take in water and swell up before the chitin in their shells hardens. This is the way all crustaceans grow. At this point, they are known as Instar 2, and they have a mouth and anus, so they can begin eating. Their diet is exactly the same as that of the adults, consisting of microscopic free-floating algae, bacteria and even some detritus, though algae makes up the vast majority of their diet. Over the next several days, they molt up to 10 more times before finally reaching adult size and form.
This basic knowledge tells us a few things about caring for and using brine shrimp nauplii as food for our fish. First and foremost, the best thing to do is use them quickly after they hatch while they are still packed with energy. The longer we wait to use them after hatching, the more energy the nauplii use up. They cannot eat in their first stage, so there is no benefit to feeding them. After the first molt, while still nutritious, they are drained of most of their initial supply of fatty acids and need to be fed (or “enriched”) before feeding them to our fish. Also, at this stage they are considerably larger, and our fry may not be able to eat them.
In addition, newly hatched brine shrimp are attracted to light. We can use a small light bulb outside the hatch container to attract the nauplii to a single area of the hatch container and gather them all up without getting too many shells or unhatched eggs mixed in with the shrimp.
How to Hatch
Hatching brine shrimp is easy. I started when I was only 9 or 10 years old back in the early 1970s, and I have been hatching and feeding brine shrimp nauplii almost every day since. I started with a simple nonaerated hatching dish that was popular at the time, but I’ve since learned that aeration greatly increases the chances of success. I use two hatchers made from 2-liter soda bottles that I made more than 20 years ago, but I realize this is overkill for most folks with only one or two aquariums and an occasional need for newly hatched brine shrimp, so what I describe in the paragraph “Making a Half-Liter Hatcher” is making a simple hatcher from water bottles. There are likely nearly as many methods of hatching brine shrimp as there are aquarists who do so. What I describe next is how I do it. This method is foolproof and has stood the test of time.
What You’ll Need
• Commercial unit or homemade brine shrimp hatcher
• Untreated tap water
• Table salt from the grocery store
• Epsom salts
• Plain household bleach with no additives
• A strainer (such as a coffee filter) to collect the shrimp
• A baster or pipette to feed the brine shrimp to your fish
Set up the hatcher following the manufacturer’s instructions in an area where splashed saltwater won’t cause a problem. The ambient temperature should be around 78 to 80 degrees Fahrenheit. If the area is too cold, you can make an insulated hatching box out of an old Styrofoam box.
If you are using the half-liter homemade unit, add 1.5 teaspoons of salt, a half teaspoon of Epsom salt, and from a pinch up to an eighth of a teaspoon of brine shrimp eggs. Add plain cold tap water; don’t bother to remove chlorine or chloramine. Add a single drop of bleach and put the cover on the hatcher. Add aeration with rigid air line tubing, cut at an angle. Adjust the aeration with a simple and inexpensive gang valve, which allows for fine-tuning of the output. You just want it to mix slowly and be well-aerated. You don’t want it bubbling out of the top. Leave it alone for 24 hours. If the air line tubing gets clogged with salt, use an untwisted paperclip to remove the clog.
After approximately 24 hours, shut off the aeration and let the water settle for about 15 minutes. I set up a night-light next to the hatcher. The bulb’s light should reach about halfway up the water column, which is where the shrimp will gather in a bright orange ball. The entire unit is set on the counter next to a sink. Using the air line tubing, siphon the water into the coffee filter and let the water flow down the drain. Manipulate the end of the air line in the hatcher and siphon as much of the orange ball of shrimp as possible without siphoning the empty egg shells at the surface or the dead eggs at the bottom.
After the shrimp have drained, rinse them under a gentle stream of cool tap water, and then invert the coffee filter into a container of clean dechlorinated water. From this, use a baster or pipette to feed the brine shrimp nauplii to your fish.
Making a Half-Liter Hatcher
Materials needed: three half-liter water bottles, a 6- to 8-inch piece of rigid airline tubing, clear packing tape, and a sharp knife or pair of scissors.
Making the Cuts
- Cut the first bottle about 2 to 3 inches from the bottom and discard the top. The bottom will become the base. (See A below.)
- Cut the bottom off the second bottle, leaving just a bit of the bottom to create a lip around what will become the top. (See B below.)
- For the third bottle, cut the bottom off about an inch from the base. This will become the cap. (See C below.)
Putting It Together
- Tightly seal the cap of bottle B, and invert this second bottle inside of bottle A. You may need to trim bottle A just a bit so that the cap of the inverted bottle sits firmly on the base.
- Tape the seam, joining the two bottles to become one hatcher.
- Cut or drill two quarter-inch holes in the cap (piece C) to allow a rigid piece of air line tubing to fit through and for air exchange.
- Finally, cut the tip of the rigid air line tubing at an angle to keep it from quickly becoming blocked. Attach an air line to the rigid tubing, and you’re in business.
Bleach kills any bacteria on the surface of the eggs, and it keeps the eggs from clumping in the hatching container. When eggs clump, the inner eggs can’t hatch. So by using the bleach, you perform two functions: sterilizing the eggs and improving the hatch rate. The bleach will dissipate by the time the nauplii hatch out.
Any widely used product that has been around for many years has an associated body of lore and myth that accumulates as “fact” when people try to explain their varied experiences with said product. Brine shrimp are no exception. Here are some of the most popular myths.
Reuse the hatch water to save money. Used hatch water is filthy with bacteria, as well as decaying unhatched and dead nauplii. Each time you reuse it, the hatch rate will decline. There is no economic or biological reason to reuse it.
Decapsulation is better than hatching because it preserves all of the nauplius’ energy. Decapsulating the eggs simply removes the cysts. The amount of energy lost to hatching is measured in nano or possibly even pico calories. It might make a difference if the fry only ate one or two shrimp, but they eat hundreds at each meal. Consuming a single extra shrimp will make up for all of the cumulative energy used in hatching.
Store brine shrimp eggs in the fish room. Brine shrimp eggs will last for many years if stored in a freezer. If kept in a warm, humid fish room, the hatch rate will decline fairly quickly.
Copper from pipes will kill brine shrimp nauplii. Even badly corroded copper pipes do not release enough copper into the water to kill brine shrimp. They can survive at many times the concentration of copper that is released by corroded copper pipes.
I hope this brief introduction has helped to demystify hatching brine shrimp and you’ll be willing to give it a try, even if you only use it as an occasional snack for your fish. They will appreciate it and possibly even reward you with fry, which you will now be able to feed. Happy fishkeeping!