The Secret Aquarium is a secret stage accessed by entering the hole in the wall on the right side of the Jolly Roger Bay room. It consists of a room fully filled with water; it contains 40 yellow coins that can be used to refresh Mario's air. There are also 8 red coins that must be collected to spawn a star. It is the only stage to have an (albeit implicit) time limit, as you cannot resurface and there are a limited amount of coins you can use to refresh your air.
Although the stage itself does not require any A presses, as it can easily be done by swimming with the B button, entering the aquarium is a challenge on its own. The current strategy used is very complicated. Because the final text redirection is done using a door that requires 1 star, the whole strat has to be done without collecting a single star. We have to enter Bowser in the Dark World, get the basement key, and go to Shifting Sand Land. Once in there, the TAS creates a setup using various objects found in the course to make sure Mario gets the right angle and speed for the lobby movement.
|4 coin rings around 4 of the red coins
|Another coin ring above the star marker
|8 red coins