Baby-Koi: Water Effect is a free live wallpaper for Android devices that offers an interactive water ripple effect. The app provides a visually appealing experience that responds to touch and device movement, which can be enabled through the accelerometer settings. The result is a dynamic and engaging wallpaper that brings your phone screen to life.

The app includes a preferences screen that allows users to customize the ripple size and enable or disable the accelerometer. Additionally, the app does not contain any push notifications or icon ads, providing a seamless user experience. To install, simply long-press on the home screen and select "Live Wallpapers."

Overall, Baby-Koi: Water Effect is a great choice for those looking to add some visual flair to their phone's home screen.