Why can thawed fish become dry and tasteless after slow freezing?

When fish is frozen slowly, the water within its cells forms large ice crystals rather than the small ones produced by rapid freezing. These large crystals rupture the cell membranes, causing significant structural damage to the fish flesh.1

When the fish is subsequently thawed, these ruptured cells release their internal water and essential flavor-providing compounds in a process known as drip. This loss of fluid leads to dehydration, which leaves the final product dry and lacking in its original flavor. To maintain the quality and texture of fresh fish, it is essential to pass through the zone of maximum ice crystal formation—between −2 and −7 °C (28 and 20 °F)—in less than one hour.12