Sprinkle 0.5-1 tablespoon of coarse salt evenly on the top and bottom of the fish, scrub it vigorously, and then sprinkle an appropriate amount of cornstarch to remove the mucus on the fish, wipe it off, and then rinse it with water.

Rainbow trout, Oncorhynchus mykiss (Walbaum, 1792), is a cold-water pond-cultured fish of the genus Pacific Salmon in the family Salmonidae. Rainbow trout is an important cold-water fish widely farmed in the world. Because mature individuals have a brown-red vertical stripe along the lateral line, which looks like a rainbow, hence the name. It is native to northern North America and the west coast of the Pacific. It mainly lives in low-temperature fresh water and has high water quality requirements for breeding waters. Rainbow trout is a food fish that has been introduced into many countries, but has become an invasive species in some areas.