You can tell that the fish is fully cooked by testing it with a fork. When you flake it using a fork, it will have lost its translucent look at the centre and will be an opaque white. If the edges are dry and hard, then your fish is overcooked. You can also press on the fish using the back of a spoon or your finger. If it flakes apart easily, it's cooked.
it depends on if you are baking it or frying it...but it better fried lol so if fried it wil start to turn brown keep flipping it then take a fork and cut in it a little to see if it is white inside...well you know turned into meat
You can tell if a fish is fully cooked by seeing the color change. If it is white throughout, then it is fully cooked. Also test the texture of the fish. Put a fork through, if it's clean, then it is fully cooked.
cook it untill it comes off the bone easily if its freshly caught fish, untill it floats if your deep frying it, either way, in the thickest part of the fish-yes, it will turn that opaque white (or pink) and loose the translucent look
In Texas when we have a big fish fry, they put a batch into 3-5 gallons of hot oil and it takes about 3 minutes till it floats, they turn it over and in about 1/2 minute it is done. The inside is white and flaky. I poach fish a lot, put slices of lemon, onion and bell pepper in the water bring water to a boil, (about 1 to 2 inches deep), put the fish slices in without any coating, cook it about 2 minutes on each side and it is done. Squeeze lemon to serve.