What Is Infusoria?
The term infusoria is an old one that has changed in meaning over the years. At one time it referred to just about any microscopic, or nearly microscopic, organism that lived in fresh water. That use of that word long ago became outdated in the scientific community. However, the term infusoria is still used by many within the aquarium community, even by younger fish enthusiasts.
To aquarium enthusiasts infusoria refers to many small organisms in water that tiny fry can feed up upon. Although it's not feasible to name every organism that could be in an infusoria culture, some of the primary ones include:
- Algae (Volvox)
Where Are Infusoria Found?
Infusoria live in a watery environment and can be found everywhere. Purified water, such as that purchased in bottles at the store is relatively free of such organisms. At the other end of the spectrum are outdoor bodies of water, which are generally teaming with many types of microscopic organisms. Even puddles water by the roadside are full of infusoria.
Like other bodies of water, aquariums also have infusoria, however the quantities are usually not sufficient to support newborn fry. Therefore, aquarium owners must grow their own cultures if they wish to have enough infusoria to feed their newly hatched fry. The items needed to culture infusoria are pretty common, easy to find, and don't cost an arm and a leg. However, before delving into how to start your own infusoria culture, it's wise to know where not to get infusoria.
Pests In Infusoria
It is not unusual for aquarists to be told to trot down to the nearest pond and scoop up some water to get a good starter culture for infusoria. However, that practice brings considerable risk. The unwary aquarist in all likelihood is carrying home considerable grief in that little jar of pond water.
In nature there are often some undesirable elements hanging out with the good stuff. Water tigers, the larvae of the diving beetle, are particularly prolific and quite nasty. They'll eat anything they can get a hold of, including your young fish. Even bugs considered beneficial, such as the water boatman, can be dangerous to small fry. The list of undesirables abound, but the short list includes some common critters such as:
Home culturing of infusoria is relatively easy and inexpensive. A multitude of methods are possible, but the basics are all the same. Take water with organisms in it, such as your aquarium water. Add some nutrients such as blanched lettuce, to promote growth of the infusoria. Wait for the infusoria to grow, then feed to the fry. Nutrient material can range from lettuce to commercially preparations such as Liquifry. The key thing is to ensure all materials used are free of pests that might harm the young fish fry. Some of the myriad of things that aquarists have successfully used to create and maintain infusoria cultures include:
- Banana peel
- Lettuce (blanched or dried)
- Pablam or other powdered cereal
- Rabbit pellets
- Raw potato
- Rice - boiled
As the infusoria grow the water will become cloudy, and in some cases movement of the infusoria can be seen with the naked eye. Examination of a drop of water under the microscope will confirm the growth of the infusoria. Some aquarists will start more than one culture to allow them to be harvested at different times. With a little practice, it is possible to keep the culture going for extended periods of time.
Using the culture is quite easy, simply siphon off a portion of the cloudy water, taking care to avoid sucking up pieces of the decaying nutrient material. Drop the infusoria-laden water into the tank with the fry to give them a tasty meal. Tiny fry require frequent feedings of infusoria until the grow large enough for other foods, such as freshly hatched brine shrimp or commercially prepared fry foods.