Members of Ciliophora move by use of cilia, small threadlike extensions of their cytoplasm that beat to push them through water. The phylum is named for this feature. Some members have modified cilia to aid in feeding as well, and these are sometimes fused into sheets for additional efficiency.
There are about 8,000 species of Ciliophora that have many distinct features that they share. Each cell has multiple nuclei, and feature what are known as macronuclei that control the cell functions and asexual reproduction, and micronuclei that control sexual reproduction. Asexual reproduction by binary fission, which creates two daughter cells, is the most common. Sexual reproduction that ends with four daughter cells is also possible. The genetic code of some Ciliophora is slightly different from other cells. Some portions of the code are interpreted differently by their cellular machinery than in other cells.
Ciliophora mostly live in freshwater environments. They eat bacteria, algae, other Ciliophora or organic debris. They frequently form relationships with bacteria, often to the benefit of both organisms. Some species form relationships with algae, giving them a greenish tint and allowing them to benefit from photosynthesis. Other species are parasites of humans and other animals. One species, for instance, is a major cause of death among captive lobsters.