A study on fish species composition and catch per unit effort (CPUE) was conducted at the Nong Han wetland in Sakon Nakhon Province, Thailand. Fish were collected with 3 randomized samplings per season at 6 stations using 6 sets of gillnets. A total of 45 fish species were found and most were in the Cyprinidae family. The catch by gillnets was dominated by Parambassis siamensis with an average CPUE for gillnets set at night of 807.77 g/100 m2/night. No differences were detected on CPUE between the seasonal surveys. However, the CPUEs were significantly different (P<0.05) between the stations. The Pak Narmkam station had a higher CPUE compared to the Pak Narmpung station (1,609.25±1,461.26 g/100 m2/night vs.297.38±343.21 g/100 m2 /night). The results of the study showed that the Nong Han Wetlands is a lentic lake and the fish abundance was found to be medium. There were a few small fish species that could adapt to living in the ecosystem.