A big bass is an abnormally large bass caught while big net fishing at any big net/harpoon fishing spot. Since players can only get it while fishing for bass, it requires 46 Fishing to catch. Big bass are a very rare catch (1/1000), and catching one prompts the message "You catch an enormous bass!" instead of the usual "You catch a bass."
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 1,000 coins and return a stuffed big bass to the player. They can then mount the fish using 2 oak planks. When players take it to the Taxidermist, she will exclaim "That's a mighty fine sea bass you've caught there."
A big bass may be cooked into a regular bass for the standard cooking experience.