A 16x16 matrix gives you only 256 pixels to work with, and most underwater scenes I have seen on grids that size end up looking cramped or washed out. This build gets around that in a way I find really charming: a full animated aquarium, complete with a working clock, tucked inside a repurposed IKEA picture frame.
The hardware side is nicely simple. An Arduino Nano drives the matrix, and the whole thing sits behind a white diffuser panel that softens the pixels into something that reads more like a scene than a grid of dots. On the software side the maker used the FastLED library, and the animation code was written roughly half with help from Claude on the free plan and half by the maker. That split seems like a sensible way to keep momentum on a hobby project, and the maker still enjoys the challenge of coding within the free plan, which I think says a lot.
The details are what sell it for me. There is a blue background, green seaweed, a multi-colored seabed, and white bubble pixels rising through the water. Fish in white and pink tones swim horizontally across the matrix, with the occasional visitor passing through. Below the matrix sits a red four-digit seven-segment display showing the time, and in the footage it ticks over from 12 10 to 12 11, which is a nice touch of life.
One open question: the title mentions WLED while the text says FastLED is used, so I am not sure which one is actually doing the work here. The internal electronics are also not clearly shown, which leaves the wiring a bit of a mystery.