B.K.A. Information pamphlet No.14 August 1966. George J. Maier. Chicago U.S.A.
When we acquire new fish the first impulse will be to breed them. If we succeed with this phase and the eggs hatch then we have to keep the fry alive in order to fulfil our ambition. Many of our larger killifish can be given newly hatched brine shrimp, but for the smaller varieties we need a live food that is smaller in size, this food is called infusoria.
This phase of the hobby seems to be the least understood and consequently has been exploited by unethical suppliers to a great extent. All kinds of worthless infusoria pills and powders have appeared on the market.
It is a known fact that if any dehydrated form of vegetation such as alfalfa or lettuce is put into water and left there for several days you'll find a great number of small animals swimming in this water. You will need a microscope to be able to identify them. Those single cell animals, called Protozoa, form the basic food for many of our newly hatched fish. If we start a culture in this manner we never know what we have since it was inoculated by air carried specimens that were in an encysted form. This method only rarely gives good results.
A good culture should consist of the rapidly multiplying Protozoa and if possible a readily propagated Rotifer in addition to it.
A short look at their way of life will help a great deal in their propagation. The most suitable Protozoa is unquestionably Paramecium. They multiply by cell division and feed on the rod shaped bacteria that are always present in immense numbers when organic matter is decaying in water. If ample food is present they multiply in astronomical proportion. Dr. Ehrenberg figured out that a single Paramecium could grow into 70 million individuals in 30 days under favourable conditions. Because of its body shape it is very often called the slipper animal. Rotifers, on the other hand, are many - celled animals. They have a heart, a stomach and digestive tract and reproduce by laying eggs.
In size they are larger than the previously described animals and for this reason can be considered a very good food animal for our young fish. The name Rotifer, or wheel animal, is derived from the fact that on either side of its "head" are cilia that are moved very rapidly so they appear to be on a moving wheel. The ones on the left side of the mouth move clockwise and those on the right side anticlockwise. This motion brings a stream of water to the animals mouth. Most animals go after food, our Rotifers create a current that brings their food to them.
Over the many years of culturing infusoria I noticed that in a young culture Paramecium are found in greatest abundance but as the culture gets older the Rotifers will take over. For practical purposes we can utilize this knowledge by feeding newly hatched fish water from a +rather new culture and as the fry grow, we feed them from the older culture containing mostly Rotifers. The easiest to raise Rotifer is Philodina.
The practical way to get a culture started is by filling a wide mouthed gallon jar with water from the hot water tap. Let it cool off and then add a piece of dried lettuce, about the size of a dollar bill or pound note. Now for the next three days check the pH every day, it should be alkaline, If it is not, correct this with small quantities of Sodium Carbonate ( Baking Soda ). After the third day a small quantity of water from a known culture is added and you are in business. Once the culture is going there is no need to worry about pH, the culture will always stay on the alkaline side unless it is polluted with to much lettuce. Once the dried lettuce sinks to the bottom it should be removed and replaced as its food value has gone. The culture should smell like stagnant pond water, it should never stink. If it ever gets foul through neglect the sediment should be syphoned off and the culture aerated for a short time. This generally takes care of the bad odour.
You feed this culture to your young fish by giving them as much as they will eat, for instance, for 300 angel fish fry, feed about 4 ozs. of the liquid. You can see the infusoria readily with your naked eye in your tank and once they are gone they should be replaced by more. Young fish should have food in front of them at all times to ensure maximum growth. On the other hand if we over-do it and put too much infusoria culture into our tank water, we are liable to deprive our fry of the needed oxygen. Common sense should be your guide here.
I brought one ounce of culture medium from a biological supply house in 1936 and have kept it going ever since. The cultures are kept on a shelf at room temperature. If for any reason you do not need your culture because you have no young fish to feed you may forget about it for as long as two months. If again needed, draw off the sediment from the bottom, replace the water, add dry lettuce and in two weeks time you will have a good culture again.
As you noticed I use dry lettuce. This I do for convenience. Whenever we have lettuce on the table the outer leaves are usually discarded. In our household they are dried and put into a plastic bag. You could use alfalfa, dried banana peels, rice, wheat or almost anything that will decay and it will do the trick, but I have had the best results with dried lettuce.
I make it a practice of always using water from the hot water tap. Just about all animal life is killed off in the hot water tank, that way I do not introduce unwanted animals into our culture.
If an infusoria culture should not be available in your immediate area, you can send for one from one of your fellow B.K.A. Members, they are mailable just like our fish and fish eggs. Several months ago I sent a culture to a Doctor in Buenos Aires, Argentina and in spite of the fact that they were kept in customs for quite a while they stayed alive and my friend in Argentina has now a good infusoria culture.