Fish Statue
From Starfy Wiki
The Fish Statues (Japanese: サカナのぞう) are three sparkling statues resembling fish that are found only in Densetsu no Starfy, in Deep Sea. One of the Buranko tells Starfy about them and how they must be pushed from either the left or right hand side.
These statues disappear once Starfy revisits the stage after Ogura is defeated for the first time, or if the player uses the demo glitch to access the Stage Select as if Ogura was defeated.
If Starfy pushes a Fish Statue from the left, the rock blocking a current of water below it will disappear and Starfy will fall through it. leading back to map 9. If Starfy pushes a Fish Statue from the right, the rock won't disappear and Starfy will be able to advance to the next room.