Along the same lines as Chip suggested, I received a whole frozen fish from an in-law that was frozen in a way I had never seen before....whole....I mean whole....head,guts, feathers, the whole works. Not kidding. The fish when thawed was absolutely fresh tasting. I attributed it to the fact that no flesh was exposed. I never used the technique myself, as it just takes up too much room, but I can tell you that it works. As a kid, my Mom used to freeze the trout we caught in a coffee can filled with water.....same idea....kept for very long times in the freezer with no burn and was fresh tasting when finally drug out and thawed.
I'm convinced that keeping the flesh covered in it's skin really helps preserve the flavor.