YouTube for Android gets a Dark theme.

Finally, Google has added a dark mode to YouTube, helping to make the app a little easier on the eyes. 

Here's how to enable it:

1. Tap your profile picture at the top right of the screen.
2. Tap settings.
3. Tap general.

Dark theme is the second option on the General page. tap the slider to enable it and voilà!

The dark theme is available in version 13.35.51. Download it in Google play store.