Cooking time depends on many factors including how much fish you are using as well as how big they are (the bigger ones take longer). Most people recommend cooking salmon steaks or fillets between 10 minutes per inch thickness (1/4 inch) at 400 degrees fahrenheit (200 degrees celsius). This means if you have 4 inches thick salmon steaks they should take approximately 20 minutes at 400 degrees fahrenheit (200 degrees celsius).