THE SCIENCE of "scale reading", or determination of the age of fish from the examination of their scales, is less than 40 years old. Yet today the publications on the subject are to be numbered by the hundreds, and there is scarcely any phase of fish and fishery work that has not been benefited by this powerful tool for investigation. Fish culture is no exception to this rule. It is because of the increasing interest of fish culturists in scale reading and their numerous requests for information on the subject, that I have been asked to prepare a brief discussion of the method of age determination in fishes.