What is Infusoria?

Anyone who has sought information about feeding newly hatched fry has probably been told to go out and get some infusoria. Easy to say, but what is infusoria, where and how do you get it, and what do you do with it once you have it?

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 That use of that word long ago became outdated in the scientific community.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)
  
• Amoebas
  
• Euglena
  
• Paramecium
  
• Rotifers
  
• Stentor
  
• Vorticella
  

Infusoria is particularly critical for anyone who is attempting to breed fish, as many newly hatched fry subsist entirely on microscopic infusoria during the early days of their lives. Having a ready supply of infusoria can make the difference been success and failure for an entire hatching of young fry.

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:

• Cyclops (water flea)
  
• Damselfly Nymph
  
• Dragonfly Nymph
  
• Hydra
  
• Planaria
  
• Water Boatmen
  
• Water Tigers
  

Needless to say, the dangers out-weight the benefits when it comes to taking water from outdoor sources to start an infusoria culture. Instead, the best option is start your own culture indoors using your own items so you can control what is in the end product.

Culturing Infusoria
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
  
• Grass
  
• Lettuce (blanched or dried)
  
• Liquifry
  
• Milk
  
• Pablam or other powdered cereal
  
• Rabbit pellets
  
• Raw potato
  
• Rice - boiled
  
• Straw
  
• Yeast
  

The container, usually a jar, used should hold several quarts to a gallon of water. Ice cream buckets have been used as well. Aquarium water is generally the best source for the water, but tap water can also be used. Some aquarists have even used the old water from a flower vase, as it is usually well populated with infusoria. Add the nutrient medium and let the whole mess cook in sunlight for several days.

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 Infusoria
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.