An underwater vacuum cleaner is mainly provided with a box-shaped body, a plurality of through holes are arranged on a peripheral surface of the body, and a cleaning brush is arranged on the opening edge of the body, and a tubular grip portion is formed on the surface. The grip is connected to the pump provided by the filter tank above the aquarium. When in use, the hand is held by the grip portion, the body is moved in the aquarium, the dirt impurities in the water are cleaned and sucked into the filter tank for filtration, so as to clean the aquarium； and when not used for cleaning, Then, the suction member is adsorbed on the inner wall surface of the aquarium, so that the sewage and the impurities pass through the body, and then filtered by the filtering water tank, so that the water reaches the circulation effect from the bottom of the aquarium, thereby forming a filtering water quality effect.一種水底吸塵器，主要係設有一盒狀之本體，於該本體的周緣面設有複數之透孔，且於本體的開口緣設有一清潔刷，表面係設有一與本體貫通之管狀的握持部，由該握持部連接於水族箱上方濾水槽所設之幫浦。俾於使用時，以手握於該握持部，將本體於水族箱內移動，將水中髒物雜質清理並吸入濾水槽過濾，以達到清理水族箱之目的；而當不使用於清理時，則藉由吸持件吸附於水族箱內壁面，使污水及雜質通過本體，再由過濾水槽予以過濾，使水達到從水族箱底部向上之循環效果，進而構成過濾水質效果。
