Step 1: Lay the fish on a cutting board. Grasping the fish's mouth, take the fillet knife and position it just behind the pectoral (side) fin. Cut downward to the backbone, keeping the spine of the knife blade up. Be careful not to cut into the fish's backbone.
Step 2: Turn the knife blade toward the tail and continue cutting, staying on top of the back and belly fins. You’ll feel resistance as you cut through the rib cage, but be careful not to cut into the backbone. It’s better to cut too shallow than to cut too deep. Continue your cut toward the tail, until you have almost, but not quite, cut the scaly fillet off.
Step 3: With the fillet barely attached to the tail, flip it away from the fish. Position your knife on the narrow portion of the fillet; while holding the fish, slice between the meat and skin to remove the fillet. To obtain the most meat, cut very close to the skin. When the fillet is removed, place it, with rib cage still attached, on a sheet of waxed paper. Flip the fish over and fillet the other side.
Step 4: Take each fillet and carefully cut out the rib cage with the tip of your knife. To keep the most meat, angle your knife and slice close to the ribs.
Step 5: After you rinse the fillets, they’re ready to cook or store.