Paramecium are single celled organisms found freshwater, brackish and marine water. They are often found growing abundantly in stagnant water.
Paramecium are used for feeding small fry as a first food after fry become free swimming.
These single celled animals are easily cultured in aged water taken from an aquarium. A small amount of timothy hay placed in the aged water and stored in a darkened location starts the culture after a seed culture of paramecium are added.
Another successful strategy is to place a banana peel in a container filled with aquarium water and left to sit in a darken area. Once again paramecium will be added to start the culture growing. As the culture will fowl a new culture can be started after a week.