Time and temperature are two inversely related variables of the cooking equation. Temperature should be about 180F if you are poaching the fish; in the low-moderate range (300 to 350F) if pan-broiling, pan-frying, or baking; 375F if you are deep-frying; and about 450F if you are broiling. Lower temperatures than the suggested guidelines would prolong the cooking time too much, which would in turn needlessly sap some of the fish's delicate flavor. Higher temperatures than recommended figures would develop more flavor, but that gain would not compensate for the resulting dryness and toughness of the flesh.
The second coordinate - time - should be as short as the cooking method allows, just long enough to coagulate the protein. Prolonged cooking - even if you use the right temperature - robs flavor and toughens the protein, and the flesh will fall apart at the slightest provocation.
Most cooks, be they the restaurant or home variety, nearly always overcook their fish. The element of error is usually in the time rather than the temperature.
** Asian Recipes