Cut off the tail. Remove the ventral and dorsal fins (the fins that run along the sides of the fish), the pectoral fins (small fins at the base of the head), and anal fins (near the rear of the fish’s belly. Use kitchen shears to cut out the gills under the flap at the base of the fish’s head. Discard the fins and gills.
Thanks to James Peterson for these instructions from his book “Fish & Shellfish”.