Oncorhynchus mykiss, commonly known as the rainbow trout, is a species of freshwater fish native to North America. They are characterized by their vibrant coloration, which includes a pink stripe along their sides and black spots on their back and fins. Rainbow trout are typically found in cold, clear streams, rivers, and lakes, where they thrive in well-oxygenated waters. These fish are popular among anglers and are often raised in fish farms for recreational fishing and food. Rainbow trout are carnivorous, feeding on insects, small fish, and crustaceans. They play an important role in aquatic ecosystems and are also a key species in aquaculture practices.