The flesh turns opaque and light pink
The flesh flakes easily with a fork
The center is slightly translucent but not raw
The internal temperature reaches 125°F to 130°F for medium-rare
The internal temperature reaches 145°F for fully cooked
The fish feels firm but still moist
The juices run clear
The flesh separates cleanly along the natural lines
The skin releases easily from the pan or grill
The color changes from translucent to opaque throughout the thickest part