AI Tool Comparison
Cartesia vs Fish Audio
A side-by-side breakdown to help you pick the right tool for your workflow.
Cartesia
Power voice agents with sub-100ms TTS that streams in real time. Sonic's architecture eliminates the latency pause that makes voice bots feel robotic.
Fish Audio
Clone a voice from a 10-second clip and generate lifelike speech via API or playground, now on the S2.1 Pro model with emotion tags, fresh off a $52M seed round.
Bottom Line
Last reviewed: August 2026
Cartesia and Fish Audio both sit in Audio, but they're built around different use cases within it. Both carry the same 4.6 rating, so the decision comes down to fit, not quality.
Choose Cartesia if…
Best for developers building conversational voice agents where natural back-and-forth pacing matters most, and its edge is sub-100ms text-to-speech latency via a streaming architecture that eliminates the turn-taking pause other TTS models have. The fastest conversational voice latency available, ElevenLabs still wins on richness and nuance of the voice itself.
Choose Fish Audio if…
Fish Audio's actual story is that it's the TTS infrastructure already running inside HeyGen and Retell in production, available directly as a standalone API and playground. That makes it the logical pick for developers who want voice cloning or speech synthesis without building on top of a consumer-facing product that abstracts away the underlying model.
| Attribute | Cartesia | Fish Audio |
|---|---|---|
| Category | Audio | Audio |
| Pricing | freemium | freemium |
| Pricing Detail | Free 10K characters/mo / $65/mo Growth | Free tier / Plus from $11/mo (annual) / higher plans to $749/mo / API pay-as-you-go from $15 per million characters |
| Rating |
Key Features
Cartesia
- Sub-100ms time-to-first-audio for real-time voice applications
- Streaming TTS: output starts before the full text is processed
- 50+ voices across accents and languages
- Voice cloning from a short audio sample
- Emotion and pacing control via SSML-style tags
- WebSocket API for low-latency real-time integration
Fish Audio
- Zero-shot voice cloning from 10-30 seconds of reference audio
- S1 flagship model with open-domain emotion and tone markers
- Pay-as-you-go API with WebSocket streaming and Python/TypeScript SDKs
- Open-weight self-hosting option under a commercial license
- Multilingual, cross-lingual speech with no phoneme dependency
Pros
Cartesia
- •Fastest TTS latency available, essential for conversational voice agents
- •Streaming architecture enables natural back-and-forth conversation pacing
- •Voice quality is competitive with ElevenLabs at significantly lower latency
Fish Audio
- •Same model quality already trusted in production by HeyGen and Retell
- •Genuinely usable free tier plus API pricing with no minimum commitment
- •Voice cloning quality holds up well even from short reference samples
Cons
Cartesia
- Premium voice quality still trails ElevenLabs on richness and nuance
- Voice cloning requires more audio samples than some competitors
- Growth plan pricing scales steeply with volume
Fish Audio
- Credit-to-minute math on the consumer plans takes a minute to understand
- Best commercial voice cloning rights require a paid plan, not the free tier
- Self-hosting the open-weight models is an enterprise-level engagement, not a quick setup