The utility model relates to a purifying device for a fish vegetable symbiosis system.Including an outer tube,I. drainage chamber,A connecting tube and a microorganism attachment medium.The top end of the outer tube is provided with a water injection port.The drain chamber is provided inside the outer pipe.The cavity wall of the drainage cavity has a plurality of perforations to connect the interior and exterior of the drainage cavity.The communicating pipe extends from the inner part of the drainage chamber to the outer part of the outer pipe.And there is an opening in the drainage chamber,The height of the opening is higher than the perforation of the drainage chamber.The microbial attachment medium is contained in the outer tube.And is located outside the drainage chamber；When the user injects water inward through the injection port of the outer pipe,The water level between the outer pipe and the drainage chamber will change repeatedly.Nitrifying bacteria and denitrifying bacteria attached to the surface of microorganism attachment medium,It can remove the total nitrogen in water.To achieve the purpose of purification.一種用於魚菜共生系統之淨化裝置，包含有一外管、一排水腔、一連通管以及一微生物附著介質，該外管之頂端具有一注水口，該排水腔是設置於該外管內部，該排水腔之腔壁具有多個穿孔連通該排水腔的內部及外部，該連通管是由該排水腔內部延伸至該外管外部，且於該排水腔內部具有一開口，該開口之高度是高於該排水腔之穿孔，該微生物附著介質是容置於該外管之內部，且位於該排水腔之外部；當使用者經由外管之注水口朝內注水時，位於外管及排水腔之間的水位會往復地變化，微生物附著介質表面所附著之硝化菌及脫硝菌，可配合地去除水中之總氮，而達到淨化的目的。
