Paramecium is a single-celled animal which is mainly found in freshwater, brackish, and marine environments. Paramecium has a characteristic slipper-like shape and the surface is covered with cilia.
Their size ranges from 50 to 330 micrometers (0.0020 to 0.0130 in) in length. Paramecium is ovoid, elongate, foot- or cigar-shaped.
Paramecium was first seen in late 17th century by microscopists (Antonie van Leeuwenhoek). In 1752 the English microscopist John Hill, first coinded the term “Paramecium”.