Rice Genomics and Genetics 2025, Vol.16, No.5, 260-266 http://cropscipublisher.com/index.php/rgg 262 advantages are not easy to achieve in fields that only grow rice. Rice-fish farming not only increases yields, but also protects the environment. It is a more stable and long-term agricultural method (Hu et al., 2016; Arunrat and Sereenonchai, 2022; Ye et al., 2024). 3 Effects on Rice Grain Quality 3.1 Appearance quality Rice-fish farming has many benefits for the appearance of rice. Indicators such as rice milling rate and transparency perform better under this method. Studies have found that rice-fish farming can significantly increase the rate of whole rice polishing, that is, the rice is more complete after milling. When fish swim in the fields, they can also reduce the chalkiness of rice grains, making the rice look brighter, more shiny, and better looking (Wan et al., 2019; Wang et al., 2023). The main reason for these changes is that there are more nutrients in the soil, fewer pests and diseases in the rice fields, and the rice grows stronger and healthier (Tsuruta et al., 2010). 3.2 Eating quality The edible quality of rice, including gelatin consistency, amylose content and taste score, has also been significantly improved in the rice-fish farming system. Studies have shown that this system can make the cooked rice softer and more glutinous, with a better taste, and consumers prefer it (Li et al., 2022). Fish excrement can provide natural nutrients, reduce dependence on chemical fertilizers, make the proportion of amylose in rice more moderate, and also affect the stickiness and taste of rice. The combination of multiple factors makes rice in the cooperative farming system more popular. 3.3 Nutritional quality The rice-fish system can also make rice more nutritious. After raising fish in the fields, the protein content in the rice increased, and trace elements such as iron and zinc, as well as some antioxidant components, also increased. The presence of fish improves the nutrient cycle of the soil and allows rice to absorb more nutrients (Tsuruta et al., 2010; Li et al., 2025). This improvement is particularly important in areas where rice is the staple food, which can alleviate the problem of insufficient nutrition intake to a certain extent and help improve the dietary health of local people. 4 Underlying Mechanisms of Quality Improvement 4.1 Enhanced soil nutrient cycling Rice-fish farming can make the nutrient cycle in the soil better, which is one of the important reasons for improving the quality of rice. When fish are raised in rice fields, they will defecate. These feces can increase the organic matter in the soil and supplement the nitrogen, phosphorus, potassium and other nutrients needed for rice growth (Nayak et al., 2018; Kaewpuangdee et al., 2024). With these nutrients, rice grows faster and better, and the quality of rice is naturally improved. In addition, when fish move in the field, they can also help speed up the decomposition of organic matter. In this way, the roots of rice can absorb nutrients faster. The nutrient flow in the entire field is also more stable and efficient (Li et al., 2025). 4.2 Alteration of microbial community composition Fish swimming around in rice fields will affect the microorganisms in the soil. This effect is good and helps the growth of rice. There will be interactions between fish and soil, which will increase the variety of microorganisms in the soil and make them more active. In this way, the soil will be healthier and nutrients will be converted faster (Nayak et al., 2018; Ranjith et al., 2024). Microorganisms can decompose organic matter and release nutrients that can be absorbed by plants. In this way, the soil is more fertile and the rice can grow stronger. A good microbial environment can also suppress some diseases transmitted in the soil, which is also beneficial to improving the quality of rice. 4.3 Regulation of plant metabolism The rice-fish system can also affect the physiological metabolic process of rice. After raising fish, there are fewer pests and diseases in the fields, and the rice is less "injured", so more energy can be used to grow taller and longer
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