Assam is a state in northeastern India where paddy is a major crop and the staple food for almost all households. About 75% of the state population is directly or indirectly dependent on agriculture, while about 69% of the workforce in the state is engaged in agricultural activities. The traditional practice of raising fish in the paddy fields probably began with the beginning of paddy cultivation itself in the region because the waterlogged paddy fields create a natural habitat for fish. However, over the years, the practice has evolved with recognition of its multi-ecological benefits. In Assam, paddy-fish integration is mostly practiced in flooded river basins, unmanageable vast waterlogged areas, and perennial waterlogged wet paddy lands. Fishes enter the paddy fields during monsoon and grow along with paddy. Fishing activities start after the recession of water during November-December and the farmers use various fishing gears and indigenous traps either operated in the paddy-free spots of the field or are fixed at appropriate water entry and exit points in the fields. These lands often remain dry from December to April. Physically, the aquatic phase starts from May to November and possesses varying water depths depending on land topography, local rainfall patterns, water tables, soil quality etc. The paddy-fish integration in Assam can broadly be classified into three categories viz., perennial system, synchronous refuge pond system and enclosure system. In the perennial paddy fish farming system, a single crop of fish is raised along with two crops of paddy viz. Ahu (autumn paddy) and Sali (winter paddy) cover nearly both seasons. In a synchronous refuge pond system, the fish crop is raised synchronously with Sali paddy during the monsoon period. In the enclosure system, the fish crop is raised with deep water paddy (Bao) in deep water areas by enclosing the plot with pegged screens. Traditionally, the waterlogged paddy fields were one of the most common fishing grounds for small indigenous fish species (SIS) for the rural people of the region during the wet season (June to November). Hence, the paddy fields were the major source of SIS production and were contributing to household nutrition in rural areas. It is an extensive level of farming practice using low to moderate input technology. In the World Bank-funded APART project, WorldFish and Govt. of Assam are working together to improvise the traditional paddy-fish culture system through multi-locational demonstrations at farmers’ fields with the objectives of introducing climate resilient paddy-fish integrated farming for improving the livelihood, income, and nutrition of smallholder farmers along with gender-equitable employment. The cost and return evaluation showed that the paddy-fish culture is much more profitable than the mono-crop paddy. The integrated paddy-fish systems have high reliability and stability and therefore better adapted to future changes. Paddy-fish systems are promising climate resilient models for climate changes and challenges that will reduce risks for smallholders and maintain productivity and sustainability.