Abstract: A bag device for preserving and protecting game-fish with primary application to billfish and the like is disclosed as including a layered insulating sheathing which is foldable about a fold line for enclosing and insulating the main body of the fish in ice with the design and capability for allowing the bill, fin and tail portions thereof to extend beyond the enclosure. Velcro fastening tape carried around the periphery of the sheath and fold line thereof effectively seals the main body portion therein and around the extended portions of the fish to avoid loss of cooling.