Abstract: The extensive use of chemicals has significantly contributed to societal progress while concurrently causing severe environmental pollution, endangering both ecosystems and human health. Consequently, toxicological studies and health risk assessments of chemicals are essential for effective pollutant risk management. Small model fish species, particularly zebrafish (Danio rerio), rare minnow (Gobiocypris rarus), and medaka (Oryzias latipes), have become invaluable models in environmental toxicology research due to their high degree of evolutionary conservation with mammals. This review comprehensively examines recent advancements in utilizing these small model fish for chemical toxicology research, encompassing standardized toxicity testing protocols, toxicokinetic and bioaccumulation investigations, and multi-level toxicological effect and mechanism studies. Special emphasis is placed on their applications in developmental toxicity, metabolic disruption, neurobehavioral effects, endocrine interference, cardiovascular dysfunction, immunotoxicity, and reproductive toxicity research. Furthermore, we critically evaluate current research limitations and propose future directions to enhance the broader application and development of small model fish in toxicological studies.