Figure 1: Making the hatching container.
There are many ways that brine shrimp (Artemia) can be hatched, including using techniques such as decapsulation. While these other methods work, and probably work well, I don't have a lot of time to play around so I use a pretty simple method that takes me around 5 minutes each day to prepare. This article details how I hatch brine shrimp, both to feed my corals and fish, and for raising for later feeding to my organisms. I have my hatching set up so that I get a crop of nauplii every morning.
My methods for hatching brine shrimp (Artemia sp.) are based very much on the methods documented by RayJay.
I keep my hatching containers at the right temperature have them in a water bath. I use the same water bath for hatching and growing brine shrimp. The bath is simply a polystyrene box, with water and a heater. The box I use I got from an LFS and it is what they receive their shipments in. It is filled* with freshwater and I have a small 75W heater set to around 25°C.
* Note it is only full of water once the hatching and grow out containers are in bath.
For each hatching container, I use a 2L soda bottle with lid that is cut in half. The top half is inverted as the container and the bottom half is used to support the top half (see Figure 1). Note that you can make a slightly deeper hatching container by using 2 x 2L soda bottles and cutting a larger top section from one and a larger bottom section from the other, discarding the other pieces. Make sure that the supporting section is deep enough to take the hatching container.
Figure 1: Making the hatching container.
My two hatching containers sit in the water bath as mentioned above. As the height of water in my water bath is quite high, I have 3 bathroom tiles under the hatching supports to keep the tops of the hatching containers above the water level of the bath.
The cysts I use are "Artemia GSL 2001 90% Grade AAA" from Primo Aquaculture Pty Ltd. The cysts come in a can which can't be resealed so I transferred mine to a clean empty peanut jar with screw on lid.
Vigorous aeration is required for part of the hatching process and so a suitable air pump and air line is required. The air should be pumped straight into the hatching container and an airstone should not be used. I use a fairly large pump so I can run multiple devices, including the hatching and raising of brine shrimp. The airline should be pushed right to the bottom of the hatching container (into the lid area of the soda bottle).
The following method takes between 34 and 40 hours for the cysts to hatch. This maybe somewhat longer than other methods, but it works for me.
I prefer to have the nauplii ready first thing in the morning to feed to my fish, so I prepare the cysts in the evening a day and half prior. For example, cysts prepared on a Sunday evening would result in nauplii being ready on the following Tuesday morning.
I clean the hatching container (if it has been used previously) and fill with fresh natural seawater to within a couple of centimetres of the top of the container and place the container on the support in the water bath. I insert the airline tube but do not turn on the air. A very small amount of cysts are added to the hatching container. I only add enough to cover one quarter to one third of the surface of the water in the hatching container.
The cysts are left for a few hours to become hydrated. I find it easier to just leave them overnight.
After the cysts have been left to soak overnight, I turn the air on to aerate the water and turn the cysts over. The aeration is quite vigorous. I turn my air on first thing in the morning. I leave aeration running 24 hours.
As I usually have two batches running, each morning I switch the aeration from one container to the other.
After aerating the hatching container with cysts for 25 hours, I turn the air off to allow everything to settle and separate out. The floating empty cysts float to the surface and those that will sink, sink to the bottom of the container. I wait around 30 minutes for everything to settle before harvesting.
I harvest the nauplii by either with a turkey baster or siphoning with airline, being careful to only draw water from the middle, avoiding the cysts on the surface and the bottom . Ideally, the water should be discarded and this can be achieve by running the collected water through netting of the correct size. When feeding fish, I often put the water and nauplii straight into the tank without any problems. When I raise the brine shrimp, I use a small net with fine holes to separate the nauplii from the water.
Last updated: 21 November 2004