Filtering unit for aquariums (1), designed to allow easy removal and repositioning of at least one filtering cartridge (20) comprising: a container (100), provided with a fluid inlet (71) and a fluid outlet to allow fluid communication thereof with an aquarium tank, inside said container a filtering path being defined which connects said flow inlet (71) and said flow outlet (73) pumping means (24) intended to move a liquid flow along said filtering path said first vertically extractable filtering cartridge (20) defining an internal volume (253) connected, via an inlet mouth (242), to an upstream portion (72) of the filtering path, said first filtering cartridge (20) being housed in a well (619) and allowing the release of the water contained in the first internal volume (253) towards said well (619), said well (619) extending vertically from above inside the container (100) and being connected to a downstream portion of the filtering path via an outflow aperture, said first filtering cartridge (20) comprising a lower impermeable portion (26), designed to retain a volume of liquid in its interior in the case of extraction from the well (619) of the cartridge.
