The easiest way to determine if salmon is fully cooked is to check if the inside has turned from translucent to opaque, and the meat slightly resists flaking or pulling away from the bone. When using a meat thermometer to check, a temperature of 145 degrees Fahrenheit is ideal.
Overcooking the salmon results in opaque meat that flakes easily, denoting a lack of moisture. Cooking salmon properly requires attention, since there is little time between cooked and overcooked. Chefs often check salmon by pressing the top of the fish. Properly cooked salmon is firm to the touch with a bit of "give" from the pressure.