Organic farming is well-known as the environmental friendly agriculture. Although many researches done in paddy fields have showed the difference in arthropod abundance between conventional and organic fields, there are few studies to reveal whether the abundance in aquatic organisms was influenced by the farming and effects of aquatic organisms on terrestrial arthropod through rice plant growth. We have conducted field studies in conventional and organic fields to compare the abundance in the arthropods. The abundance of mosquito larvae was higher in conventional, while the biodiversity in aquatic ecosystem was higher in organic fields. Abundance in mosquito larvae might influence on abundance of polypagous like spiders as numerical response after they emerged adults. Results revealed abundance in spiders at conventional was higher than organic fields where the abundance in larval mosquitoes was low. In addition, many pond snails were observed only in organic fields, although there were a lot of tadpoles in both fields. We carried out 2x2 factorial experiments to reveal how presence of a snail and tadpoles influences on rice plant growth. Growth of rice plant at the treatments with a snail and tadpoles tended to be higher than other treatments. We would discuss the influence of aquatic organisms on abundance of terrestrial arthropods and rice plant growth.