An aquarium filter having a housing unit for mounting on the wall of the aquarium tank with an intake chamber for receiving contaminated water and a filtering chamber for filtering the contaminated water and passing it back into the aquarium. A removable intake tube transfers the water from an inlet end to an outlet end where it can flow from the aquarium tank to the intake chamber. A slidable control valve selectively exposes bypass ports on the outlet end to regulate the flow rate of the aquarium water from a maximum down to shut-off, and all values therebetween.