A free, cozy 3D aquarium that runs right in your browser, nothing to install. It's a living reef with Octopus Boy, a little octopus who lives in a cave, crawls around on the sand and changes colour, plus rays, wrasses at a cleaning station and coral that glows at night. You earn fish sticks to unlock new things, so the tank slowly becomes yours. Lots of people just leave it running in a tab. There's also a Windows version that works as a real screensaver across multiple monitors with AAA graphics: https://windows.fishtankplus.com (Microsoft Store: https://apps.microsoft.com/detail/xp8c5d95n4q26p). Free, no ads. Solo dev, built with a lot of help from Claude, ChatGPT and Grok.
Just watch and relax. Feed the fish, tweak the fish count, speed and lighting, and unlock new things with fish sticks. On the full site you can turn on the webcam real-3D effect, which makes it feel like looking into a real aquarium.
Fish Tank Plus was submitted to SlowDen by Technology 83. SlowDen did not make this game - it is published here from the developer's own submission, added on 2026-10-30. It runs in the browser with no download, no install and no sign-up.