BettaFish (åūŪč) is a multi-agent public opinion analysis system that automates the end-to-end process of gathering, analyzing, and reporting on public sentiment across 30+ Chinese social media platforms. The system is built around four specialized agents: QueryEngine (news breadth search via Tavily), MediaEngine (multimodal search via Bocha), InsightEngine (database mining via SQLAlchemy), and ReportEngine (template-based report generation with intermediate representation and HTML/PDF/Markdown rendering). A ForumEngine coordinates agent collaboration through log monitoring and LLM-generated moderator comments. The architecture is a monolithic Flask application that manages multiple Streamlit sub-applications and CLI tools, with a separate MindSpider crawler subsystem for data collection. While primarily an application, it includes significant data/research components such as sentiment analysis model training scripts (BERT, GPT-2, Qwen3, traditional ML), a Weibo sentiment dataset, and data pipeline scripts. The system relies heavily on external LLM APIs (OpenAI-compatible), search APIs (Tavily, Bocha, Anspire), and system dependencies (Playwright, WeasyPrint). The codebase demonstrates solid engineering with reusable patterns like robust JSON parsing, chart validation/repair, and a hardened GitHub Actions star-history script, but suffers from significant code duplication across engines and tight coupling to external APIs.