An improved structure of the aquarium filter includes a filter cloth made of nonwoven fabric with small pores and high density that is installed on the outermost layer of the filter, an activated carbon filter sheet that wraps within the filter cloth and can deodorize smell and filter impurities, and a filter net made of resin foam with large pores and low density that wraps within the activated carbon filter sheet. The filter is made of filter materials in multiple layers that are formed individually by one single process so that the production cost can be reduced. Furthermore, a support frame is installed on the aquarium. A support platform is set on the support frame on which the planting unit sits. The filter is placed on the uppermost support platform. Nutrients generated from the decomposition of fish excreta in the water are absorbed by plants.
