Microscopic View of InfusoriaWater may contain living organisms, this group of organisms is loosely defined as infusorians. they are excellent food for baby fishes and are practically a necessity for every newborn tropical fish.

Most of the infusorian animals are classified in the phylum Protozoa. In this gigantic phylum are found species, which live not only in fresh water but also in salt water, species that live in dry desert sands, species that live inside the bodies of humans and animals as parasites, species that live in and on the soil, and species that live alone or in colonies. For the tropical fish breeder all that really necessary is to be able to recognize infusorians when present. the technique of pure cultures is too bothersome for the ordinary aquarist, and a mixed infusorians culture serves well to feed the fry in their various sizes.

An ordinary low-power microscope magnifies enough to enable one to distinguish when a culture is teeming with life or when there is barely an infusorians present. Sometimes larger protozoa's can be observed with an ordinary hand lens when the culture is held up to a strong light.

More important for the hobbyist is how to obtain infusorians and how to culture them. the prime source of an infusorians culture is a pond, preferably a pond with green water. A cupful of this green water should contain millions of living organisms. Other sources are the bottom ooze of ponds, decaying aquatic plants, and ordinary air, for the spores and cysts of protozoan are found everywhere. the bacteria, molds, and possibly the algae only outnumber them.

Once some living specimens have been found there will be no trouble, but in the wintertime when ponds are frozen over and when outdoor collection is difficult, there is still another method of starting an infusorians culture. On the market in most aquarium shops there is such a thing as "infusorians pills." When placed into conditioned aquarium water these pills issue forth a volume of infusorians. then again, if these pills aren't available, try a few pieces of dried or decaying lettuce.

Place the lettuce, infusorians pills, or green water in quart jars or enamel pans or any other suitable rustproof container. If the material is dry add enough water to cover it. Maintain this container in a warm place, preferably not in direct sunlight. Within 48 hours the culture will progress and if they are properly fed will continue to multiply until after about 15 days they become overpopulated and start to die off. At this time the culture must be changed.

Feeding the infusorians is easy. Boil lettuce, grass, or leaves of some kind for 20 minutes in just enough water to cover. When cool add the vegetation and liquor remaining in small amounts to the culture. the culture need be fed only once, when it is first set up. Sometimes lima beans or rice can also be used without boiling. Set these grains in the culture dishes a few days before they are inoculated with the culture.

At times a culture will grow so rapidly that it will start to give off an odor; it should be changed at this time.

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