Don't wait too long to consume your cooked bluefish fillet. Ideally, bluefish is consumed on the same day, it's just better that way. You may notice a deterioration in the quality and taste of the flesh if you leave it overnight or a couple of days before you eat it. You might want to explore an escabeche recipe, which is preserving the bluefish fillets in vinegar, like it is done with mackerel.