Excerpt from Common Parasites of Fishes Fish taken commercially, for sport, or raised by fish fanciers are sometimes found to be abnormal due to injury, deformity, disease, or the presence of parasites. This paper is concerned with common parasites of fishes and their recognition. Life cycles and biology are mentioned briefly, and references to more detailed literature are included. Parasites may be defined as animals that live on or in another animal, the host, at the expense of that animal. There are many kinds of parasites which may be found on the surfaces of fish, including the gills, as well as in the flesh and internal organs (fig. Those on the surface are known as external parasites, and those that live inside are called internal parasites. Several types may occur together in a single fish. Some parasites are fairly large (up to several inches) and can be seen easily, but many are microscopic. Scientists who work on parasites describe the organisms, study the life cycles (some have several intermediate hosts), survey the kinds and numbers found in fish, study damage done to fish, and attempt to control them. Re search is carried on by the U. S. Fish and Wildlife Service and some colleges and universities. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.