Q: At a restaurant, I was recently asked what temperature I wanted my fish cooked. How do I know?
A: Chances are, you ordered salmon or tuna, because most other types of fish, like flounder, sole, snapper, tilapia and shellfish are simply cooked through until they are no longer translucent. No dining decisions to make there. Tuna and salmon, on the other hand, are more steak-like and can be prepared anywhere from rare (about 110 degrees) to well-done (about 145 degrees), depending on your preference. (For the record, the USDA says 145 degrees is the minimum safe internal temperature for fish.)
Tuna and salmon are often served rare; seared on the outside and raw inside, for a nice variation of taste and texture. If you like sushi, chances are you will like that preparation. When cooked all the way through, tuna tends to dry out, so I wouldn’t order it past medium; whereas, the fat in salmon keeps it moist even when well done. If you are not sure what you prefer, one reply that is a good bet is “however the chef recommends it.”