This study investigated the characteristics of fish communities and river health in the Gyeryeongsan National Park, Korea from May to September 2021. The survey collected 26 species belonging to nine families from 22 survey stations. The dominant and subdominant species were Zacco platypus(26.4%) and Rhynchocypris oxycephalus(26.1%), respectively. The next most abundant species were Zacco koreanus(21.1%), Squalidus gracilis majimae(11.0%), Pungtungia herzi(3.4%), Iksookimia koreensis(2.6%) and Rhinogobius brunneus (2.5%). Among the fish species collected, 12(46.2%) were Korea endemic species, including Rhodeus uyekii, Acheilognathus koreensis, Squalidus gracilis majimae, Microphysogobio yaluensis, Zacco koreanus, Iksookimia koreensis, Pseudobagrus koreanus, Silurus microdorsalis, Liobagrus mediadiposalis, Coreoperca herzi, Odontobutis platycephala and Odontobutis interrupta. Additionally, one exotic species(ecosystem-disturbing species Micropterus salmoides) and one landlocked species (Rhinogobius brunneus) were collected. As a result of community indices, the dominance(0.67~1.00), diversity(0.136~1.658), evenness(0.123~1.988), and richness(0.201~2.031) differed significantly by stations. Also, river health(index of biological integrity) was assessed as very good(seven stations) and good(15 stations). Gyeryeongsan National Park had a relatively well-preserved river ecosystem, but several disturbance factors(weir was installed at nine stations, river work was underway at five stations, and ecological disturbance species, M. salmoides were introduced into the Yongdong Reservoir area. The stable populations of fish in Gyeryongsan National Park require a river ecosystem protection plan and a systematic management plan for ecological disturbance species, M. salmoides.
