NEW HAMPSHIRE AQUARIUM SOCIETY

Subject: My Brine Shrimp Hatcher

By:Lawrence L. Feltz

According to a reprint from The Guppy Roundtable, the heart of every guppy fishroom should be the "Brine Shrimp Hatchery". The room should be designed around it. The hatching of brine shrimp should not be an afterthought. Most of the guppy fishrooms I have seen have made some provision for hatching brine shrimp, frequently using 2 liter plastic containers (inverted soda bottles). I prefer to use inverted one gallon glass jugs (a glass gallon wine jug).

I cut off the bottom using a system Larry Konig presented in his publication Portrait Of The Guppy ( Elizabeth, NJ: E.G. Publishing Co., 1967, p. 89.)

He says, "I cut off the bottom by wrapping heavy string around the bottle one an one half inch from the bottom, soak the string with lighter fluid, light it and let it burn and as it begins to sputter out, let some cold water drop on the bottom and the bottom cracks off. The sharp edge that is left can be smoothed and rounded down with sand or emery paper, be careful... this is very sharp. In this cutting operation, the jug should be inverted to stand with bottom end up in a wide mouth jar or pot that will allow it to stand straight up. Do not hold by hand, until cut and cold. After the edge is sanded and dry, wrap a few layers of heavy tape completely around and just under the edge. This helps to prevent any easy fractures from slight taps, and never pick up a cut jug by lifting on its edge; always pick them up by the shoulder of the jug."

I made two of these inverted bottomless jugs back in the 1970's, I used them daily for about seven years and then, when life circumstances forced a hiatus in my fish keeping, put them into storage. In 2001, I brought them out of storage and have been using them daily since October of that year. The tape is gone, but with the exception of a single hairline fracture (which effectively mended itself when leaking brine solution dried along the crackline creating a seal), they are as good as new.

To keep the brine in place, I jam the neck with a drilled rubber stopper (I got mine from a high school science lab. You can buy one at a specialty store that sells brew supplies - home made beer or wine makers use them in the course of their avocations). The stopper seals, and the 3/16 inch drill hole allows for the passage of the standard 3/16 inch airline tubing we all know so well.

I built a wood box to contain two of these inverted bottomless glass shrimp hatcheries (side by side). The horizontal center board I constructed from 3/4 inch plywood (mine was 9-1/2-x- 19-1/2 inches, but the dimensions are not critical). I cut two round holes (about 5 inches in diameter) side by side (about 3 inches apart) each slightly smaller than the diameter of the glass jugs (mine are about 6 inches). I then used a wood rasp to taper the shoulder of the individual holes to better match the sloping contour of the shoulder of the glass jug. The finished center board, looking a bit like a miniature two-seater-out-house, held two jugs in comfort, side by side.

I made two sides (each about 10-x-20) and a back (aprox. 20-x-20) to support the center board. I mounted the center board up 10 inches from the bottom to give me space to work, and to house the two coils of 3/16 air tubing (one from each jug, passing up through the drilled rubber stopper).The center board is about 9 inches down from the top. This space permitted a light bulb to drop down in between the two inverted jugs providing heat without ever touching the jugs themselves. This top space also functions efficiently to stop the brine solution from flowing out when the tubing is raised above the level of fluid inside the jugs. When the 3/16 airline tube is lowered, it serves as a drain to empty the shrimp hatcher of its contents.

I originally used the hatcher in an unheated space and needed the heat from the bulb to raise the temperature of the water to 85 degrees Fahrenheit, the recommended temperature for efficient hatching. My original version had an insulated cover lined with reflective aluminum foil. Through the top I cut a single hole for a light bulb to be screwed in from the inside of the box (through the lid) with the bulb socket, switch and cord outside the box. To retain heat I also made a swinging front door that opened when collecting the shrimp.

Later, when I installed two old steam radiators in my fish room, I relocated the hatcher on wood strips fashioned to match the slots between the radiator tubes. I did away with the lid, the front door, and the light bulb as a heat source. Today my fish room is heated with electric space heaters to about 75 degrees. To get the temperature of the brine up the next 10 degrees (to 85), I modified the box to use a single 40 watt bulb held in my original home-made fixture fashioned from a meat loaf tin. I keep this light at the bottom of the box (underneath the centerboard). In winter it is on 24 hours a day. I do not use a cover. I do have a front door that I attach at night (to concentrate the heat) but remove during the day (I like to see the brine bubbling, and I find I don't need to concentrate the heat for the entire 24 hour period).

With this set-up, brine shrimp can be hatched in about 24 hours using an airstone (or a length of solid plastic tubing) attached to an air source and dropped down into the narrow neck of the hatchery. When the shrimp have hatched, remove the airstone, lower the 3/16 airline tubing to drain the contents through a "brine shrimp net" into another container (i.e. a plastic gallon milk bottle). The net collects the contents (newly hatched brine shrimp, egg casings of the hatched shrimp, and any unhatched eggs that may remain). The net and its contents can then be dealt with separately. The captured brine solution can be reused. I use mine over and over again, replacing it maybe once a month. While I haven't encountered any problem, most writers recommend a more cautious approach suggesting the use of fresh brine solution with each batch as a disease preventative.

As an improvement on this set-up, I now use the 3/16 airline tubing to bubble air up into the brine (thus eliminating the need for an airstone) in the hatching phase and as a drain tube as described earlier when collecting.