Wikipedia:Today's featured article/January 23, 2015

The rainbow trout (Oncorhynchus mykiss) is a species of the salmon family native to cold-water tributaries of the Pacific Ocean in Asia and North America. Those that spend their lives in streams and rivers average between 1 and 5 lb; others, called steelhead trout, live in the ocean or the Great Lakes for two to three years before returning to fresh water to spawn, and may reach 20 lbs. Coloration varies widely, but all adult fish are distinguished by a broad reddish stripe along the lateral line, from gills to the tail, which is most vivid in breeding males. Wild-caught and hatchery-reared forms of this species have been transplanted and introduced for food or sport in at least 45 countries. Introductions to locations in the U.S., Southern Europe, Australia and South America outside the fish's native range have damaged native fish species when the trout has preyed on them, out-competed them, transmitted contagious diseases, or hybridized with closely related species. Some local populations of specific subspecies, or in the case of steelhead, distinct population segments, are listed as either threatened or endangered under the Endangered Species Act. The steelhead is the official state fish of Washington.

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