1, look at the gills. Fresh gills are tightly closed, bright red in color, and the color of the gills of the unfresh fish is dark gray.

2, look at the fish eyes. Fresh fish eyes a little outwardly protruding. Eyeballs bright black and white, not fresh fish, eyeballs turbid and even fall out.

3, look at the mouth. Fresh fish mouth tightly closed together, not fresh fish mouth is generally separate, there will be a paste mouth situation.