Objectives To comprehensively understand the current situation of fish diversity in Songyinxi Wetland Park and to provide data support and scientific theoretical backing for the protection work of fish diversity in Songyinxi Wetland Park.

Methods From January to December in 2022, an analysis was conducted on the composition of species diversity, fish fauna, ecological types and threatened status of the fishes in Songyinxi Wetland Park. This analysis was carried out through field investigations and sampling, combined with historical literature materials.

Results A total of 72 fish species were recorded. With the exception of six alien species, the remaining 66 species were all native inland fish, belonging to 56 genera, 17 families, and 6 orders. In terms of species diversity composition, the predominant group was Cypriniformes, which encompassed 47 species. With regard to the fish fauna-complex, except for six alien fish species and one migratory fish species, the other 65 fish species can be classified into five fish faunal complexes. The fish faunal complexes of the river plain fauna complex and southern plain fauna complex were dominant, with 40 and 17 species respectively. The 66 inland fishes can be divided into three ecological categories based on their habitat: Rheophilic fishes (15 species), Limnophilic fishes (50 species), and Catadromous fishes (1 species). Of the 66 fish species, Anguilla japonica was classified as Endangered, and Onychostoma barbatulum was classified as near threatened.

Conclusions The Songyinxi River was one of the main tributaries of the upper reaches of the Oujiang River and exhibited a relatively high fish species diversity. However, due to its location within the central urban area of Songyang County, the middle section of the wetland park was susceptible to human-induced disturbances. This study established a foundation for long-term monitoring of biodiversity in Songyinxi Wetland Park.