First I flash froze the fresh, whole fish loose on pans in the freezer.
When they were solid,
I dipped them in water and refroze them a number of times
until they were encased in a 2-3 mm thick layer of ice.
This keeps the fish in better shape as it prevents oxidization and freezer burn.
Then I bagged them up, to be stored in the freezer for up to 3 months, and thawed in the fridge as needed.