Abstract: A dirt sucker for an aquarium includes mainly a compressing ball, a flexible long tube and a residue collector. The compressing ball is provided with a valve in its two ends respectively and connected with a short tube extending outwards at the two ends respectively. One of the tubes is connected with an adjustable switch for controlling flow rate or temporarily stopping suction. The flexible long tube is connected with one of the short tubes at one end. The residue collector, connected with the flexible long tube, is to be inserted among stones placed on the bottom of an aquarium to let dirt accumulated on the stones sucked out together with the water in the aquarium by repeated compression of the compressing ball, and the residue collector is provided with a filter in the interior.