Many fishmarkets will bone or fillet your fish for you. Fish is best bought absolutely fresh, and you can recognize this first by its appearance. A fresh fish will still have its natural coloring. If it was full of brilliant blues and greens, you should still see them. Colors fade as the fish loses its freshness. Steely mackerel begins to look dull. Salmon loses its silvery sheen. Rainbow trout starts to lose its moist coating. In a fresh fish the eyes will look full and bright. White, sunken or dry eyes are signs that the fish is no longer fresh. The gills should be red. Also, a fresh fish is stiff and firm with its scales tightly fitting. When it is no longer fresh it becomes limp and its scales begin to flake off. The smell is also important. Fresh fish has a most agreeable smell: a breath of ozone, iodine and sea air. Any hint of an unpleasant smell should warn you immediately that the fish is not fresh.