Feeding fish nowadays is not usually a problem. Whatever the fish eats there is something commercially available that is suitable, be it a flake, pellet, freeze dried, sheet or frozen variety. Among the foods available as frozen are brine shrimp, which have been used by aquarists for very many years.
The popularity of brine shrimp isn’t surprising because so many small and medium sized fish eat them with gusto. They are convenient too when stored frozen until needed.
Occasionally a retailer is known who can supply live shrimp, but these supplies seem to be less available nowadays and if a supply is found it is often unreliable.
Frozen brine shrimp are suitable but are they as good as live ones? I am not a nutritionist but suspect that a live shrimp will be more sustaining than a frozen one, particularly if the live one is used fairly soon after hatching.
Rearing brine shrimp is very straightforward and easy. There are kits available for the purpose, but it is just as easy to modify some easily obtainable items.
The items required are a small seawater container, such as a plastic food storage box often supplied with a lid (lid not required). Anything will do though; it does not have to be seawater safe. The box needs to be large enough to accommodate a small heater/stat, the smallest one available as there will be very little seawater to heat. Actually, it doesn’t even need to be seawater; tap water will do as the brine shrimp will not go in it. Next needed are an air pump and some airline. Again the air pump should be small as a lot of power is not needed. The final requirement is a plastic drink bottle with a body about 3 to 4″ in diameter, with a screw-on plastic cap.
The plastic drink bottle should have the body shortened. The length can be obtained by ensuring the screw-on cap is in position, and placing the bottle upside down in the container so that the cap is on the bottom. The cut point should be about ½” or a little more above where the surface of the water in the container will be. The bottle can easily be cut with a sharp knife, such as those used for craft work.
Next drill a hole in the centre of the cap for the airline to fit into. Drilling a hole slightly too small is good as this will ensure a watertight fit.
Put the modified bottle in the container and keep it upright with string or anything available and suitable. Appearance doesn’t matter as the whole thing can be kept out of sight if desired.
Now we’re ready for shrimp production. Obtain some eggs from the internet or the local retailer. Reading the box will probably show that only a very small amount of eggs are required to produce a lot of shrimps!
Fill the bottle to ½” or so below the top with seawater, keep some from a routine seawater change. Replace this seawater before each batch of eggs is put in. (Note that the salinity may need to be increased depending on where the eggs were collected. Check the instructions for this. The amount of salt needed will be very small if it is needed at all.) Fill the container to ½” or so from the rim, this time using tap water if desired, though seawater will do. Turn on the heater, which should be set to a temperature between 75 and 80 deg F. Leave it all alone until the water in the container has reached this setting (the heater indicator will turn off). It won’t take long as there isn’t much water to heat.
Now turn on the air pump and if necessary using an airline clamp adjust so that the seawater inside the bottle is moving vigorously. The water outside the bottle will heat it.
Put an appropriate amount of shrimp eggs into the lemonade bottle. In about 36 hours there should be a 90% hatch or better.
These little newly hatched shrimp are nutritious and very attractive to small fish and are also caught by some corals. They can be left for a while if the aquarist wishes to grow them on, but note that once the yolk sac (attached to each shrimp) is gone if they are not fed they will begin to deteriorate. Feeding them to the aquarium inhabitants is best if done within 12 hours or so of hatching.
Getting them out is simple. The egg shells are not wanted and these, by using the following method, can be avoided. There are eggs available that have been de-shelled and so the shrimp could be caught without the assistance of a light.
The shrimp are attracted to strong light. Obtain a torch, some airline and a fine net. Turn off the air pump and wait for a short while for the turbulence to die down. Shine the torch into the bottle and the shrimp will rise toward it. Siphon them out into the net.
Ok, fish and corals, here they come. They will soon be gone, as the livestock seem to recognize the meal and vigorously chase them down. Watch the corals, are they capturing? Some probably are.
It’s all very easy. There isn’t much equipment and modifying the bottle is straightforward. The set-up does look a bit unprofessional, but it can be kept out of sight if desired. A regular supply of shrimps is simply arranged, mixed in with other types of food for variety. Once set-up, activation takes minutes.