Objective To study the acute toxicity of tetrodotoxin to zebra fish. Methods The maximum non-lethal concentration (MNLC) and 10% lethal concentration (LC10) determinations were used to assess the acute toxicity of tetrodotoxin. Results According to the simulation calculation of Origin 8.0 software, the MNLC was 8.62 µmol/L and 15.2 µmol/L for LC10. Under the experimental conditions, tetrodotoxin at a concentration of 16.0 µmol/L and above induced pericardial edema and arrhythmia, leading to the death of zebra fish. The target organs for acute toxicity of tetrodotoxin were the heart and liver. The main manifestations were pericardial edema, arrhythmia, and delayed yolk sac absorption. The toxicity appeared at a concentration of 0.958 µmol/L. Conclusion Tetrodotoxin has heart and liver toxicity to zebra fish, and its toxicity is dose-dependent.