Fresh Tuna Tuna Color Chart. The color should be pink. Size and shape #1 tuna should be at least 60 pounds or larger since heavier fish have a more desirable loin size and fat content.

The color should be pink. Tuna should be firm to the touch. Size and shape #1 tuna should be at least 60 pounds or larger since heavier fish have a more desirable loin size and fat content.