I have found the map of the dungeon and I can see the room that more than likely contains the boss key for Catfish’s Maw. I don’t know how to get to it though. I have been through the dungeon a bunch of times. I have been through all of the stairs that are visible on the map and none of them bring me to the location of the key. How do I get to the room that has the boss key chest in this dungeon?
If you look at the map, you will see that one room has a pool of water in it. The pool of water is deep enough for you to swim in. Jump into this and dive. It will bring you into a little cave and at the other end you will be at the room that contains the boss key.