Fish is very fragile and cooks quickly, so you must be careful to catch it before it becomes dry and overcooked. As a fish cooks, its translucent flesh turns opaque; when it’s opaque at the thickest part (test by inserting the tip of a knife), or just slightly translucent at the very center, you know it’s done. Do not wait for the flesh to flake—by that time it’s already too dry. We swear by the Canadian Fisheries Cooking Theory, which estimates the total cooking time of any fish to be ten minutes for every inch of thickness, measured at the thickest part. This works for whole fish, steaks, or fillets, whether grilled, broiled, fried, poached, or baked. Try it—it’s amazingly accurate.