Rice-fish integration is, a symbiotic farming system where fish are reared in rice fields. Although this farming method widespread in many Asian countries, it is relatively new to Sri Lanka, and consequently information on its ecological functions under Sri Lankan context is scarce. Therefore, detailed investigation on the ecological function of rice fish integration would provide necessary information to establish rice-fish integration in Sri Lanka. This study followed a qualitative case study approach, including literature review and extensive document analysis. The results highlighted the rice-fish integration approach presents an array of ecological functions, underscoring its potential as a sustainable agricultural practice. Ecologically, the presence of fish in the system contributes to increase nutrient availability for rice plants, and biologically control weed and pest. Further, rice-fish integration promotes soil fertility of rice fields which improves growth and nutrient uptake of rice plants. The rice plants, in turn, play a pivotal role to maintain biodiversity in rice fields through water purification, establishing optimal water temperature conditions, and providing an array of micro habitats for a diverse aquatic fauna and flora. On the other hand, rice fish integration promotes water use efficiency, higher economic return and animal protein requirement of local farming communities. Considering ecological, economical and health benefits, integration of tilapia fish with suitable rice varieties available in Sri Lanka is proposed. In conclusion, the rice-fish integration is an ecologically balanced farming system which has a potential to enhance the sustainability of rice field farming systems in Sri Lanka.