|World(s)||Jolly Roger's Lagoon|
Inside the Big Fish is an area in Jolly Roger's Lagoon in Banjo-Tooie. It is located in the Big Fish Cavern. Merry Maggie and a Jinjo can be found in here. To gain access to this area, you must first shoot out all of the big fish's teeth with Grenade Eggs. There are two paths in this area, one leads to Merry Maggie, while the other leads to a Jinjo. The floor and walls in the big fish move when you touch them. The insides of the fish are all red and pink including the water. There are two keelhauls within the fish.
- The Big Fish is similar to Lord Jabu-Jabu, a giant fish that swallows the player whole, from The Legend of Zelda: Ocarina of Time, because in both games you must go inside the large fish to rescue an amphibian like creature. In both games, the walls of the insides are similar in color and move around.
- After the teeth have been shot out they will stay on the bottom of the ocean floor for a while.
- It appears that the path to Merry Maggie is the fish's actual stomach. It's not known what the path that leads to the Jinjo is suppose to be.