Author(s): P NATARAJAN
With the increasing demand for fish as human food , aquaculture both in freshwater and salt water is rapidly developi ng over the world. In the developing countries, fishes are being raised as food. In many countries fish farming is a very important economic activity. The most recent branch, mariculture, has shown advances in raising fishes in brackish, estuarine and bay waters, in which marine, anadromous and catadromous fishes have successfully been grown and maintained. The parasites and diseases of fish constitute one of the most important problems confronting the modern fish culturist. Pathological conditions resulting from parasites and diseases assume high magnitude under crowded and unnatural conditions. Under such circumstances, losses from communicable diseases can reach catastrophic proportions.