Fugu Ultra vs Nano Banana 2 (Gemini 3.1 Flash Image)
Fugu Ultra (2026) and Nano Banana 2 (Gemini 3.1 Flash Image) (2026) are frontier-tier reasoning models from Sakana AI and Google DeepMind. Fugu Ultra ships a 1m-token context window, while Nano Banana 2 (Gemini 3.1 Flash Image) ships a 131k-token context window. This comparison covers specs, pricing, API access, capabilities, benchmarks, input and output token costs, and production fit for coding and agent workloads.
Fugu Ultra fits 8x more tokens; pick it for long-context work and Nano Banana 2 (Gemini 3.1 Flash Image) for tighter calls.
Decision scorecard
Local evidence first| Signal | Fugu Ultra | Nano Banana 2 (Gemini 3.1 Flash Image) |
|---|---|---|
| Best for | reasoning-heavy apps, multimodal apps, and tool-calling agents | reasoning-heavy apps and multimodal apps |
| Decision fit | Coding, RAG, and Agents | Long context and Vision |
| Context window | 1m | 131k |
| Cheapest output | $30/1M tokens | $60/1M tokens |
| Provider routes | 2 tracked | 1 tracked |
| Shared benchmarks | 0 shared | 0 shared |
Decision tradeoffs
- Fugu Ultra has the larger context window for long prompts, retrieval packs, or transcript analysis.
- Fugu Ultra has the lower cheapest tracked output price at $30/1M tokens.
- Fugu Ultra has broader tracked provider coverage for fallback and procurement flexibility.
- Fugu Ultra uniquely exposes Function calling, Tool use, and Structured outputs in local model data.
- Local decision data tags Fugu Ultra for Coding, RAG, and Agents.
- Local decision data tags Nano Banana 2 (Gemini 3.1 Flash Image) for Long context and Vision.
Monthly cost at traffic
Estimate token spend from the cheapest tracked input and output route or tier on this page.
Fugu Ultra
$11,500
Cheapest tracked route/tier: Sakana AI <=272K tokens
Nano Banana 2 (Gemini 3.1 Flash Image)
$15,400
Cheapest tracked route/tier: Google AI Studio
Estimated monthly gap: $3,900. Batch, cache, alternate speed tiers, and negotiated pricing are excluded from this local estimate.
Switch friction
- No overlapping tracked provider route is sourced for Fugu Ultra and Nano Banana 2 (Gemini 3.1 Flash Image); plan for SDK, billing, or endpoint changes.
- Nano Banana 2 (Gemini 3.1 Flash Image) is $30/1M tokens higher on cheapest tracked output pricing, so quality gains need to justify the spend.
- Check replacement coverage for Function calling, Tool use, and Structured outputs before moving production traffic.
- No overlapping tracked provider route is sourced for Nano Banana 2 (Gemini 3.1 Flash Image) and Fugu Ultra; plan for SDK, billing, or endpoint changes.
- Fugu Ultra is $30/1M tokens lower on cheapest tracked output pricing before cache, batch, or negotiated discounts.
- Fugu Ultra adds Function calling, Tool use, and Structured outputs in local capability data.
Specs
| Specification | ||
|---|---|---|
| Released | 2026-06-22 | 2026-05-28 |
| Context window | 1m | 131k |
| Parameters | — | — |
| Architecture | Composition of Experts | Decoder Only |
| License | Proprietary | Proprietary |
| Openness | Proprietary | Proprietary |
| Commercial use | Commercial use: conditional | Commercial use: conditional |
| Knowledge cutoff | - | 2025-01 |
Pricing and availability
| Pricing attribute | Fugu Ultra | Nano Banana 2 (Gemini 3.1 Flash Image) |
|---|---|---|
| Input price |
| $0.50/1M tokens |
| Output price |
| $60/1M tokens |
| Providers |
Capabilities
| Capability | Fugu Ultra | Nano Banana 2 (Gemini 3.1 Flash Image) |
|---|---|---|
| Vision | Yes | Yes |
| Multimodal | Yes | Yes |
| Reasoning | Yes | Yes |
| Function calling | Yes | No |
| Tool use | Yes | No |
| Structured outputs | Yes | No |
| Code execution | No | No |
| IDE integration | No | No |
| Computer use | No | No |
| Parallel agents | No | No |
Benchmarks
No shared benchmark scores are currently available for this pair.
Deep dive
The capability footprint differs most on function calling: Fugu Ultra, tool use: Fugu Ultra, and structured outputs: Fugu Ultra. Both models share vision, multimodal input, and reasoning mode, so the practical split is not just feature count. Use those differences to decide whether the page is about raw model quality, agentic coding support, multimodal ingestion, or predictable structured API behavior.
For cost, Fugu Ultra lists tiered pricing: <=272K tokens is $5/1M input and $30/1M output; >272K tokens is $10/1M input and $45/1M output, while Nano Banana 2 (Gemini 3.1 Flash Image) lists $0.50/1M input and $60/1M output tokens on the cheapest tracked provider. A 70/30 input-output blend puts Fugu Ultra lower by about $5.85 per million blended tokens. For tiered rows, this cheapest-track view can understate interactive or fast-lane spend, so compare the tier you will actually use. Availability is 2 providers versus 1, so concentration risk also matters.
Choose Fugu Ultra when long-context analysis, larger context windows, and broader provider choice are central to the workload. Choose Nano Banana 2 (Gemini 3.1 Flash Image) when vision-heavy evaluation and lower input-token cost are more important. For production, rerun your own prompts through the exact provider, region, and tool stack you plan to ship.
FAQ
Which has a larger context window, Fugu Ultra or Nano Banana 2 (Gemini 3.1 Flash Image)?
Fugu Ultra supports 1m tokens, while Nano Banana 2 (Gemini 3.1 Flash Image) supports 131k tokens. That gap matters most for long documents, large codebases, retrieval-heavy agents, and conversations where earlier context must remain visible.
Which is cheaper, Fugu Ultra or Nano Banana 2 (Gemini 3.1 Flash Image)?
Fugu Ultra lists tiered pricing: <=272K tokens is $5/1M input and $30/1M output; >272K tokens is $10/1M input and $45/1M output. Nano Banana 2 (Gemini 3.1 Flash Image) lists $0.50/1M input and $60/1M output tokens on the cheapest tracked provider. Compare the tier you will actually use; cheap async pricing can overstate savings for interactive workflows. Provider discounts or batch pricing can still change the final bill.
Is Fugu Ultra or Nano Banana 2 (Gemini 3.1 Flash Image) open source?
Fugu Ultra is listed under Proprietary. Nano Banana 2 (Gemini 3.1 Flash Image) is listed under Proprietary. License labels affect whether you can self-host, redistribute weights, or rely only on hosted APIs, so confirm the upstream license before deployment.
Which is better for vision, Fugu Ultra or Nano Banana 2 (Gemini 3.1 Flash Image)?
Both Fugu Ultra and Nano Banana 2 (Gemini 3.1 Flash Image) expose vision. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface.
Which is better for multimodal input, Fugu Ultra or Nano Banana 2 (Gemini 3.1 Flash Image)?
Both Fugu Ultra and Nano Banana 2 (Gemini 3.1 Flash Image) expose multimodal input. The better choice depends on benchmark fit, context budget, pricing, and whether your provider route exposes the same capability surface.
Where can I run Fugu Ultra and Nano Banana 2 (Gemini 3.1 Flash Image)?
Fugu Ultra is available on Sakana AI and Vercel AI Gateway. Nano Banana 2 (Gemini 3.1 Flash Image) is available on Google AI Studio. Provider coverage can affect latency, region availability, compliance posture, and fallback options.
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Last reviewed: 2026-06-22. Data sourced from public model cards and provider documentation.