A Tiny Desk Tank Where Every Fish Has Its Own Mind

Kert Gartner has released ASCII Aquarium, a project that runs on a Cheap Yellow Display, the $15 ESP32 dev board with a built-in touchscreen that has quietly become the default canvas for weekend hackers. The screen shows a live aquarium scene rendered in glyphs. Each fish drifts, schools, turns around, brightens, avoids the others, and chases food when you tap the glass. Hackaday picked it up on May 24.

The technical move that matters: nothing is canned. The fish are not playing pre-baked animations. Each creature has its own behavior loop and responds to stimuli in its own way, which is why the tank feels like a small terrarium that happens to live in a screen. There is a hidden menu with configuration options, a clock mode so the tank pulls double duty as a desk clock, even a display flip mode for anyone who has a beamsplitter on the desk. Open source on GitHub. The 3D-printable enclosure is a separate file you can drop into your printer over the weekend.

This is what we mean by the shift from maximum functionality to maximum well-being. A $15 screen does not need to be a notification surface. It can hold a small world that knows when you tap it. What happens when more of the screens around us behave like terrariums instead of dashboards?