A generic term used to describe any type of filtration that is powered by an electric pump. They can either hang on the side of a tank or be submerged in it, and contain an internal pump to draw water through it. They provide mechanical filtration, and optionally chemical or biological filtration.

a box shaped filter that is hung on the back of an aquarium

a chamber filter that sits on the out side of the tank hanging to the inside, the water falls like a water fall

A filter that usually hangs on the back of an aquarium. Contains a built in water pump that draws water up an intake tube from the aquarium into and through the filter medium and then returned back into the aquarium.

A filter that usually hangs on the back of your tank and contains a built in pump that draws water up an intake tube from the aquarium into and thru the filter, and then poured back into the tank.