The aquarium vacuum is a cleaning device adapted for use with aquarium. The aquarium vacuum is adapted for use in cleaning algae from the walls and corners of an aquarium while water is in the aquarium. The aquarium vacuum comprises a scrubbing device, a pump, and a filtration unit. The scrubbing device is used to remove the algae from the aquarium wall and corner. Algae released from the aquarium wall is drawn into the filtration unit with the pump. The filtration unit removes the algae and other particulate matter from the water before returning the processed water back to the aquarium.