Ultra Aquarium

A free 3D reef screensaver and live wallpaper for Windows that spreads one tank across all your monitors.

Ultra Aquarium is a living 3D reef for Windows 10/11 (64-bit) that runs as a screensaver or live wallpaper. On multi-monitor setups it becomes one big tank, with fish swimming from screen to screen, and you can set your bezel width so the picture lines up across the gaps. Press F to drop food in and watch the fish come up for it. The newest resident is Octopus Boy, who lives in a cave under the big rock, changes colour to blend in and comes out more at night. Quality 1 runs on laptop graphics, quality 10 is for a proper GPU.
It's free, but it isn't open source (the code on GitHub is viewable for inspection only). It was built with a lot of help from AI models (Claude, ChatGPT, Grok). It collects anonymous usage data by default, and you can turn that off with "Share anonymous usage" on the app's About page.

Tags: screensaver, live wallpaper, aquarium, windows, multi-monitor