Over the years a few people have told me that due to a loss of flavour, they do not freeze fish and only eat them fresh.
Certainly a well cared for fresh fish has a slight flavour edge on one that’s been frozen, but not enough difference to avoid freezing your catch. For most of my life I’ve been serving fish that has been frozen, so far without any complaints. The big secret is how well the fish is cared for from the time it’s caught until it is frozen. Just like the computer phrase, “Garbage in-garbage out”, poorly handled fish will make a poor meal.
Unlike red meats, which are aged to make them tender, fish have no connective tissue, so they spoil or at least lose quality very quickly. Fish should be killed, bled, and put on ice right away to retain their firmness and flavour. A fish left on the floor of the boat changes color very quickly and the skin wrinkles as it dries out. This is all part of the spoiling process and can be prevented by using a cooler containing ice or freezer packs, which is kept out of the sun.
Fish intended for the freezer should get to the freezer quickly but can be kept for a number of days on ice in vacuum packages or in appropriate size Ziplocs with all the air squeezed out. The quality of the fish will deteriorate rapidly if you leave them whole or unwrapped, even on ice, because the melt-water starts the spoiling process.
To be frozen, fish should be filleted and packaged into mealsized portions to avoid wastage. Vacuum sealing is the best option, but as above, an air-exhausted Ziploc will also work for short-term freezing. When frozen, these plastic bags can be easily damaged in the freezer by rough handling, so be gentle with them. If you have the time and energy, an additional wrap of butcher paper over the plastic bags gives an extra layer of protection. When the packaging is damaged, the frozen product will quickly get freezer-burned, which is simply the dry environment in the freezer drawing off all the moisture from the fish.
Fish will also keep well frozen in water in a container such as a milk carton or Tupperware container. While this routine works to keep the flavour in, the packages are bulkier and take much longer to thaw prior to cooking. The vacuum-sealed or Ziploc packages can be thawed in tepid water much more quickly and with minimal mess.
Thawed fish should be used quickly so that it ends up cooking as soon as possible after it’s finished thawing.
At our house we regularly eat pike, lake trout, and salmon from the previous summer, and in early winter, ling cod from the previous winter is common.