Lonely Planet review
Rimming the eastern and northern edges of town is 123-sq-km Nong Han, Isan's largest natural lake. Fishermen, who tie up their boats just east of Srinakarin Park, will take you out sightseeing, including a stop to visit Ko Don Sawan (Paradise Island), the lake's largest island which serves as a meditation retreat for monks. The going rate is around 400B for three people. Don't copy the fishermen and swim in the lake: it's infested with liver flukes, which can cause a nasty infection known as opisthorchiasis.
The nearby Fishery Station has an aquarium with fish from the lake as well as the Mekong and Songkhram rivers.