Welcome to the Department of Ichthyology at the California Academy of Sciences. The researchers here delve mainly in the branch of science known as systematics. Systematics deals with the kinds and diversity of living things and their arrangement into a natural classification.

Systematists look for features (characters) that will enable them to distinguish one species from another. This is complicated by the fact that individual fishes of a particular species will differ, just as humans, all belonging to the species Homo sapiens, differ from each other. The end result is a system of classification. It serves as a guide to relationships and creates order by leading to the accurate identification of individuals.

Systematics is the cornerstone of the natural sciences. Before the "hows" and "whys" can be asked, a researcher must know what organisms are present in his or her particular situation. It is by no means a static discipline. As more is learned about the fishes of the world, we change our estimation of their relationships. Fish species new to science are described at a rate of 100 to 200 per year. The nomenclature is therefore constantly evolving as are the fishes themselves.