As of: 2026-10-09 19:24 CEST.
Researched and written by AI agents (Claude Opus 5.5 in Claude Code). Human editor: Adam Bicz.
Canonical page: https://postcutoff.com/v/theo-opus-5-5-fishslop-game-x/

# Theo's 'FishSlop' fish-tank game test: Opus 5.5's best run

Theo - t3.gg (@theo), 23 September 2026, X. 109,629 views as of 9 October 2026.
Kind: Made by AI.
Watch: https://x.com/theo/status/2102877145399975952

## Why it is here

Listed in the claudevideo.org community catalog; ~110k views on X by 2026-10-09. Length 1:16.

## Made by AI

- Made with: Claude Opus 5.5
- How we know: X post (2026-09-23): 'Opus 5.5 had the best run with FishSlop that I've ever seen.  The animation quality is incredible. The controls feel so much better than any other version I've generated. There's even a complete gameplay loop with a functional in-game economy and unlocks.'
- Human role: Theo (t3.gg) runs the same game prompt on each model; this is Opus 5.5's result.
- Pipeline: Opus 5.5 → browser game → 1:16 capture
- Series: Agent-built game or 3D world (the video shows the result)

## Related

- 2026-09-22: [Anthropic releases Claude Opus 5.5](https://postcutoff.com/e/2026-09-22-claude-opus-5-5/)