There are literally dozens of different do-it-yourself brine shrimp hatchery models out there (I provide links to some of these at the end of this article). Notwithstanding how many times this road has been trod, I too have designed my own brine shrimp hatchery, which I'll share with you here. I have two models, actually. I like the first more than the second because it is easier to set up and to harvest shrimp, but building it requires a little more effort and $. The second model is very similar to others' models and is cheaper and simpler to make. However, set up is a little bothersome at times.
This first model can be made using either wood or Plexiglas. I prefer Plexiglas, but wood works, and the same idea could be done using any kind of plastic container, I guess. In fact, if you have an old fish aquarium, it could be used. The basic idea is to make a container that has a divider, sparing a 1/8" slit along the bottom. 1/3 of the container is without light to hatch the eggs and the remaining 2/3 is lit. Unhatched eggs stay on the dark side until they hatch, when they migrate to the lighted side where they can easily be collected with a brine shrimp net. The dark portion of the hatchery will need to be opaque and have a lid so that no light can enter
Here's what you'll need:
▪ 4 - 4" x 4" pieces of black 1/8" Plexiglas (for the walls)
▪ 1 - 3 7/8" x 3 7/8" pieces of black 1/8" Plexiglas (for the divider)
▪ 1 - 4 1/8" x 1 1/2" pieces of black 1/8" Plexiglas (for the lid)
▪ 1 - 4 1/8" x 4 1/8" pieces of black 1/8" Plexiglas (for the floor)
▪ Methylene chloride (to glue the pieces together)
The good news is that while Plexiglas is a little bit more expensive than most media, these pieces are small enough that they won't cost you too much, especially if you hunt the bargain bins.
If you decide to use wood instead of Plexiglass you won't need the Methylene chloride, but you will need silicone to seal the seams and epoxy paint to waterproof the wood.
If you have not yet read my article Working With Acrylic, I encourage you to read it before beginning this project. Working with acrylic, or Plexiglas, is not difficult. There are just a few things you need to know before starting.
To assemble the pieces, refer to the diagram above and the one to the right. Unless you glue the sides as demonstrated to the right, neither the lid nor the floor piece will fit. The second most important aspect of the assembly is to leave no larger than a 1/8" opening at the bottom of the divider. What I would recommend doing is placing a scrap piece under the divider while you glue it. Just make sure the scrap piece is small enough to slip out once the divider has been glued. You want the slit under the divider to be small enough that the brine shrimp have to actively swim out, otherwise you'll end up with lots of cysts in the collecting chamber. This can be a problem since many fish (including Cichlids) can get intestinal blockages from eating unhatched cysts.
There are couple of things you can do to get the lid to form a light-proof seal around the top of the hatchery. You can either rouder a 1/8" perimeter on the lid or you could glue a piece of styrofoam to the bottom of the lid. I am sure there's other options I haven't thought of that would also work.
As you may have already known or learned from my article on Brine Shrimp, brine hatch best in water with a temperature ranging from 68ºF to 86ºF. Note: For the Artemia strain a temperature of 75ºF is ideal. If you need to artificially raise the temperature of your water you can easily add a heater to the collecting chamber. Although you probably don't need it if you're just hatching brine (versus growing them up), you can also add an air stone to the chamber.
Once the hatchery is complete and has set for 24 hours, you're ready to begin. This container has a volume capacity of 1 liter; therefore, add 1 Tablespoon of aquarium salt (i.e., rock salt) or synthetic sea salt. Fill the hatchery with warm water, stirring it to ensure all of the salt dissolves. Now add 1 - 2 teaspoons of brine shrimp cysts to the dark chamber, depending on how large a yield you want. Place the lid on the hatching chamber and turn on the air stone (optional) and heater (also optional). Within 24 hours you should expect to see little baby brine shrimp swimming in the collecting chamber and can expect them to continue hatching for another 24-48 hours after that. To collect them turn off the air stone and scoop them out with a brine shrimp net. You may find using a lamp to attract them helps. Feed them directly to your fry. To start a new batch, dump out the water, rinse the hatchery and follow the directions all over again.
I got my inspiration for this hatchery in an Aquarium Frontiers Magazine from several years back now. This model is a little bit more simple in its construction design than the previous and works just as well, but as I have already mentioned, harvesting the baby brine can require a little more effort. All you'll need is a 1-gallon milk jug with a screw-on cap, an air stone, and airline tubing.
Cut off the bottom of the jug then poke a hole through the cap just large enough for the airline tubing to squeeze through. This will form a water-tight seal. The milk jug will be used upside-down. So to support it, you can use the bottom portion that you cut off. If this doesn't work, you could use a 6" bowl. Note, this is just to support the jug, not catch water so just about anything could be used.
Fill the jug with 1 Tablespoon salt and with warm water up to 1" ABOVE the milk jug handle. This is important. Turn the air stone on and add 1-2 teaspoons of brine shrimp eggs to the jug. Within 12-24 hours (depending upon your climate), enough water will evaporate off that the water level will be below the top of the jug handle. When this happens, all the shells will collect in the milk jug's handle. Oddly enough, the shells will stay in the handle regardless of how low the water level gets. Meanwhile, the hatched brine shrimp will be swimming around in the main part of the milk jug.
There are several ways to collect them. You can either scoop them out with the trusty brine shrimp net or siphon them out. To siphon them, disconnect the airline tubing from your pump and take the airstone off. Be careful though, because once the airline is disconnected from the pump, it will need to be elevated above the water level in the jug or else all your brine shrimp will come pouring out. You should wait a minute or two for the brine shrimp to settle to the bottom of the jug or you can attract them there with a light. When ready, take the airline tubing and holding the brine shrimp hatchery above the fry tank, let the critters siphon out and into your fry tank. If you are concerned about the salt or extra water, you could pour the brine shrimp into your brine shrimp net and then feed them.
Note: Your rate of evaporation may vary from mine, depending upon your climate of course. So figure out how much water you will need to add to your jug before trying to hatch the brine. Fill the jug and see how much water evaporates off in 24 - 36 hours with an air stone. Once you know this, fill your jug to the top of the handle plus this much more. □