ABSTRACT
Rainbow trout is one of about 70 species of salmonids that occur in the natural environment. They are found in most of the cold waters of the north temperate zone, including Africa, north of the Atlas mountains, northwestern Mexico, and Taiwan. The salmonid family comprise Pacific salmon (Oncorhynchus sp.), Atlantic salmon, trout (Salmo sp.), char (Salvelinus sp.), graylings (Thymallus sp.), whitefish (Coregonus sp.), and several other genera.
