This section is from the book "The American Woman's Cook Book", by Ruth Berolzheimer. Also available from Amazon: The Domestic Arts Edition of the American Woman's Cook Book.
Fresh and Frozen Fish - Fresh fish, or fish that was frozen while fresh, has full or bulging bright eyes, bright red gills, firm and elastic flesh and fresh odor. Be sure that the flesh along the back-bone smells fresh; it spoils there first. Fresh fish sinks in fresh water. If it floats, it should not be used.
As soon as fish comes from the market, clean it and put it into the refrigerator or other cool place until it is needed.
Fish that is frozen immediately after it is caught, and is kept frozen until the time for cooking does not lose its flavor. It is preferable to clean and draw it without thawing, but if it is too hard to handle soak in cold water or allow to thaw in the refrigerator overnight until just flexible. Skinning is sometimes easier than scaling. Then it should be cooked at once without further thawing. Quick frozen fish on the market today is cleaned and ready for use. Cook at once without thawing, allowing only slightly more than the usual time allotted to broiling or baking as the case may be.