Located at the mouth of the Yangtze River estuary， Shanghai is one of China's major commercial ports and ornamental fish trade hubs， boasting a well-developed aquaculture industry. Therefore， a systematic investigation into the species， distribution， and invasion risks of alien fish introduced to Shanghai's natural water bodies is warranted. In this study， environmental DNA metabarcoding （eDNA Metabarcoding） was employed to survey alien fish at 82 sampling sites in Shanghai during spring and autumn， detecting a total of seven alien fish species. The identified alien fish was assessed for invasion risk using the Aquatic species invasiveness screening kit （AS-ISK）， and their potential habitat suitability was predicted using the Maxent model combined with climate data and distribution records. The results indicated that the mosquitofish （Gambusia affinis）， largemouth bass （Micropterus salmoides）， and channel catfish （Ictalurus punctatus） exhibited high invasion risks （BRA > 42.5） in the AS-ISK assessment， necessitating prioritized monitoring. In contrast， the paddlefish （Polyodon spathula） and mrigal carp （Cirrhinus mrigala） initially showed low invasion risks （BRA < 40）. However， when accounting for future climate change， the invasion risk of mrigal carp escalated from low to high （BRA + CCA > 47.5）. The Maxent model predicted that areas near the lower reaches of the Huangpu River estuary generally had high habitat suitability for the detected alien fish， while mrigal carp showed higher suitability in Dianshan Lake in western Shanghai. Additionally， Nile tilapia（Oreochromis niloticus） and marble goby（Oxyeleotris marmorata） were detected in the survey. However， since both species are intolerant to low temperatures and cannot overwinter in Shanghai， they were excluded from the invasion risk assessment and habitat suitability predictions. Timely identification of the species and distribution of alien fish in natural water bodies is crucial for preventing biological invasions， highlighting the need for focused monitoring of high-risk species and regions with high habitat suitability for alien species. Environmental DNA technology provides a cost-effective and efficient tool for long-term alien fish monitoring.