The present invention relates to a functional filtering apparatus for an aquarium, which receives water from the aquarium through a pipe line, purifies the water by a filtering agent, and recirculates the water to the aquarium by a pump. More specifically, provided is a functional filtering apparatus for an aquarium, which comprises: a water tank having a first outlet which is formed on the upper part of the front side of an inflow chamber and protrudes to discharge water through an overflow, a drop space which is formed on the lower part of the front side of the first outlet and is connected so that the water falls and flows into a first filtering chamber, and a water channel which is formed in the front of the first outlet and is connected to a second filtering chamber via the drop space； a bridge which is axially installed on the lower part of the first outlet and drops the discharged water into the drop space by rotation or is connected to the water channel； a path conversion means connected in order to connect the bridge to the water channel by lifting the bridge when a first buoy ascends and drop the water into the drop space by lowering the bridge when the first buoy descends； an inflow water opening and closing means formed in order to close the pipe line when a second buoy ascends and open the pipe line when the second buoy descends. Accordingly, the functional filtering apparatus reduces energy consumption by reducing the use of power, and is also easily operated. In the case of shutting power, an overflow of water in a filtering tank can be prevented.본 발명은 관로를 통해 수족관으로부터 물이 유입되고, 여과제를 이용하여 물을 정화한 후 펌프를 이용하여 상기 수족관으로 물을 재순환시키는 수족관용 기능성 여과장치에 관한 것으로서, 구체적으로는 유입실의 전방 상부에는 오버 플로우를 통해 물을 배출하도록 돌출된 제1 배출구가 형성되고, 상기 제1 배출구 전방 하부에는 물이 떨어지도록 하면서 제1 여과실로 흘러들어 가도록 연결되는 낙하공간이 형성되며, 상기 제1 배출구 전방에는 상기 낙하공간을 지나 제2 여과실로 연결되는 수로가 형성된 수조； 상기 제1 배출구를 하부에 축 설치되어 회전을 통해 상기 배출되는 물을 낙하공간으로 떨어뜨리거나 상기 수로로 연결하는 브릿지； 제1 부구가 상승시 상기 브릿지를 들어올려 수로에 연결하고 상기 제1 부구가 하강시 상기 브릿지를 내려 물이 낙하공간
