As noted on Reddit, Apple recently released a new batch of underwater screensavers for the Apple TV 4K and Apple TV HD.
The new screensavers showcase marine life and ecosystems, ranging from dolphins off the coast of Costa Rica to coral reefs in the Red Sea near Egypt. Other additions display moon jellyfish off the coast of Alaska, waves breaking on the shores of Tahiti, golden cownose rays off the coast of Mexico, and more.
Apple TV displays a screensaver after it has been idle for a short period. To change the number of minutes before a screensaver starts, go to Settings > General > Screen Saver and select Start After. You can also start a screensaver at any time by pressing the Menu button on the Siri Remote while on the tvOS home screen.
A tap on the Siri Remote provides information on where a screensaver was filmed, while a swipe left or right will change the location of the screensaver that is displayed if multiples have been downloaded.
New screensavers can be downloaded daily, weekly, or monthly via Settings > General > Screen Saver > Download New Video. While it is not possible to choose a specific screensaver on the Apple TV, 9to5Mac's Benjamin Mayo maintains a website that showcases all of the available scenes.
