Claude Opus 4.5 vs Sakana Fugu Ultra

Pick Sakana Fugu Ultra if you want the stronger benchmark profile. Claude Opus 4.5 only becomes the better choice if you want the cheaper token bill or you would rather avoid the extra latency and token burn of a reasoning model.

Sakana Fugu Ultra is clearly ahead on the provisional aggregate, 100 to 75. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

Sakana Fugu Ultra's sharpest advantage is in knowledge, where it averages 95.5 against 66.2. The single biggest benchmark swing on the page is Terminal-Bench 2.0, 59.3% to 82.1%.

Sakana Fugu Ultra is also the more expensive model on tokens at $5.00 input / $30.00 output per 1M tokens, versus $5.00 input / $25.00 output per 1M tokens for Claude Opus 4.5. Sakana Fugu Ultra is the reasoning model in the pair, while Claude Opus 4.5 is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use. Sakana Fugu Ultra gives you the larger context window at 1M, compared with 200K for Claude Opus 4.5.