The invention relates to the different steps of a method applied to frozen fish, such as tuna, in the corresponding facilities for the production of cooked fish. According to the method, the main body of the corresponding fish is selected, with the fillets separated from the head and tail by cutting the piece of frozen fish. Next, the fish fillets are defrosted in a controlled manner, cleaned and, subsequently, a solution of additives is injected into the fillets. Next, by means of a first vacuum packing step, the fillets are cooked in a water bath and then undergo controlled cooling at between 0°C and 5°C, followed by a second vacuum packing step. The fillets are then placed in cold storage for the subsequent sale of the product.
