A big swordfish is an abnormally large swordfish caught while fishing at any cage/harpoon fishing spot. It is obtainable by both barbarian fishing and by normally fishing swordfish using a harpoon. Since players can only get it while fishing for swordfish, it requires 50 Fishing to catch. Big swordfish are a very rare catch (1/2,500), and catching one prompts the message "You catch an enormous swordfish!" instead of the usual "You catch a swordfish."
It can be mounted in a Skill Hall in a player-owned house. Before it can be mounted, it must be stuffed by the Taxidermist in Canifis, where she will charge 2,500 coins and return a stuffed big swordfish to the player. They can then mount the fish using 2 teak planks. When players take it to the Taxidermist, she will exclaim "Don't point that thing at me!"
A big swordfish may be cooked into a regular swordfish for the standard cooking experience.