Fish cooking temperatures are important to monitor in order to insure meat is safely cooked to the proper temperature. When preparing fish, use the chart below as a guide to check doneness when the fish is oven baked, pan-fried, deep-fried, grilled, and steamed.o cook fish steaks that are slightly translucent in the center, remove the steaks from the heat when they reach an internal temperature of 135ºF to 140ºF. The fish steaks will continue cooking with the retained heat if they are covered and left to stand a few minutes prior to serving.