With the exception of frozen, sashimi-grade fish, fish for raw service should be purchased whole. The main reason is that it is easier to determine the freshness of a whole fish than that of a fabricated piece of fish. Look for the following freshness indicators:
- Aroma is fresh, mild, and briny, with no fishy odor.
- Eyes are moist and convex, or bulging, and not dry or sunken.
- Gills are brightly colored and moist, not brown or gray and sticky.
- Scales are shiny and tightly attached, not dull in color and falling off.
- Blood behind the cavity membrane is a bright red or burgundy color, not brown or black.
- Flesh is intact, firm, and springy to the touch, not split open and mushy in texture.