Infusoria is a collective term for many species of tiny organisms such as ciliates, algae and even small invertebrates which exist in fresh water bodies. Infusoria
are considered ideal food for baby fish.
Hence, many aquarists have their own infusoria culture tanks. Infusoria can be easily cultured from decomposing vegetative matter.
Place a lettuce leaf in a jar of water
Add an algae wafer
In a few days, you will see that the water is cloudy as both bacteria and infusoria establish themselves.
The cloudy water is due to the bacteria.
Over a few days, you will notice tha the water has cleared as the infusoria have eaten the bacteria.
At this point, it is possible to see minute creatures swimming in the water.
Aquarists will keep a culture of infusoria in a bottle. This culture can be used to produced infusoria when necessary in a short period of time.