Trust the smell and the seller.

Ask the fishmonger directly: “Is this sushi-grade?” If they hesitate, walk away. Real sushi-grade tuna smells like clean ocean water, not fishy or metallic. Look for a deep, uniform red or ruby color—no brown spots or rainbowing. The flesh should be firm and spring back when touched, not mushy.

Most markets that sell sushi-grade tuna will have it displayed on ice or in a refrigerated case, and they’ll usually label it. If it’s not labeled, ask when it was caught. Ideally, you want tuna that was flash-frozen on the boat to kill parasites—that’s the real definition of sushi-grade.

If the market doesn’t get regular deliveries of fresh tuna, skip it. Your gut is a better guide than any checklist.