Fish Audio / Fish Speech S2

Fish Audio / Fish Speech S2 is an open-source text-to-speech model developed by the Fish Audio team. It generates high-quality speech from text with voice cloning and multilingual support, and is primarily used for self-hosted TTS, real-time voice agents, and high-volume speech synthesis. Its key differentiator is the combination of near-ElevenLabs quality with full self-hosting capability and ultra-low latency (under 150ms first-token). As of April 2026, Fish Speech S2 is free to self-host (MIT license, runs on consumer GPUs) with a cloud API at approximately $0.015 per 1,000 characters. Compared to ElevenLabs, Fish Audio delivers 85-90% of the quality at roughly half the API cost, with the added option of unlimited free self-hosted inference.

What It Does

Fish Speech S2 is an open-source TTS model (MIT license) that generates near-ElevenLabs quality speech with voice cloning, multilingual synthesis, and ultra-low latency under 150ms, free to self-host on consumer GPUs or available via cloud API at $0.015/1K characters (Fish Audio). The model runs locally on 8GB+ VRAM hardware with full weights available on GitHub and Hugging Face (Fish Audio GitHub). Quality approaches ElevenLabs at roughly half the API cost, and is free with self-hosting.

Who It’s For

• Developers needing on-premise TTS: the primary reason to choose Fish Audio over ElevenLabs. Full control, no data leaves your servers.
• High-volume API users: if you need millions of characters per month, self-hosting eliminates per-character costs entirely.
• Latency-sensitive applications: voice agents, real-time conversational AI, gaming dialogue where milliseconds matter.
• Privacy-conscious projects: healthcare, legal, government contexts where audio data cannot go to third-party clouds.
• Open-source builders: developers who want to fine-tune, modify, or integrate TTS deeply into custom products.

Pricing

Fish Audio is free to self-host (MIT license, consumer GPU) with a cloud API at ~$0.015/1K characters, roughly half the cost of ElevenLabs’ $0.030/1K characters (Fish Audio).

Self-hosting cost is your own compute. Cloud prices verified 2026-04-13. Check fish.audio for current rates.

Key Features

• Open-source model: full model weights available under MIT license; fork, fine-tune, embed, or sell products built on it with no vendor lock-in (Fish Audio GitHub).
• Self-hostable: runs on consumer GPUs (RTX 3080 and up) with full local inference, no API calls, and no per-character costs (Fish Audio Docs).
• Ultra-low latency: streaming inference with first-token latency under 150ms on modern GPUs, critical for real-time voice agents and conversational AI (Fish Audio).
• Near-ElevenLabs quality: in blind A/B tests, Fish Speech S2 is within 10-15% of ElevenLabs quality. For most applications, the difference is not noticeable.
• Multilingual: supports English, Chinese, Japanese, Korean, and other languages with natural-sounding output.
• Voice cloning: clone a voice from a short audio sample. Quality is good, though ElevenLabs Professional Voice Cloning is still slightly better.

Limitations

Fish Audio’s cloud platform is less polished than ElevenLabs, self-hosting requires GPU infrastructure management, and voice cloning quality is slightly below ElevenLabs Professional Voice Cloning in side-by-side comparisons (Fish Audio).

• Not as polished as ElevenLabs. The cloud platform (fish.audio) has a simpler UI, less documentation, and fewer pre-built integrations. ElevenLabs has a more mature developer experience.
• Self-hosting requires technical skill. You need to manage GPU infrastructure, model updates, and inference optimization. Not plug-and-play for non-technical users.
• Voice cloning quality gap. Voice cloning works well but is not quite at ElevenLabs Professional Voice Cloning level. The gap is small but audible in side-by-side comparisons.
• Smaller community. Fewer tutorials, plugins, and third-party tools compared to ElevenLabs. Growing, but still niche.
• Model updates depend on maintainers. Open-source sustainability risk, though the project has strong momentum and backing as of April 2026.
• No voice agents platform. ElevenLabs has a full voice agents product. Fish Audio is a TTS model; you build the agent layer yourself.

Bottom Line

Fish Audio / Fish Speech S2 is the best choice for developers who need self-hosted TTS with near-premium quality and zero per-character costs, but ElevenLabs wins if you want a polished cloud platform with the best voice quality and zero infrastructure management. If you are a developer comfortable managing GPU infrastructure, you can get near-ElevenLabs quality for free.

Best Alternatives

• ElevenLabs: the market leader. Better quality, better ecosystem, higher price. Best if you want turnkey cloud TTS.
• Voxtral (Mistral): cloud API, cheaper than ElevenLabs. Not open-source, not self-hostable.
• Coqui TTS: another open-source TTS option. Lower quality than Fish Speech S2 but simpler to deploy.
• OpenAI TTS: good quality, easy API. Cloud-only, no self-hosting.

FAQ

Is Fish Audio free? Yes, Fish Speech S2 is fully free and open-source (MIT license) for self-hosting. You need a GPU with 8GB+ VRAM to run it locally. The cloud API at fish.audio also has a free tier with limited daily characters and watermarking. Self-hosting eliminates all per-character costs.

How much does Fish Audio cost? Self-hosted Fish Speech S2 costs $0 (you provide the GPU hardware). The cloud API costs approximately $0.015 per 1,000 characters, which is roughly half the cost of ElevenLabs ($0.030/1K chars). Self-hosting is the most economical option for high-volume use.

What are the best alternatives to Fish Audio? ElevenLabs is the best alternative if you want the highest quality TTS with a polished cloud platform ($5-$330/month). Voxtral by Mistral offers cloud API at $0.016/1K characters. Coqui TTS is another open-source option but with lower quality than Fish Speech S2.

Related

• Category: AI Voice / TTS

Sources

• Official website
• GitHub Repository
• Documentation