A bacterial film normally forms at the water surface of almost all aquaria inhibiting gas exchange and often, particularly in saltwater aquariums, forming an unpleasant scum. The Skim box is a surface skimmer that removes the film and consequently improves the oxygen supply to the aquarium. It is easily installed inside any aquarium with suction cups mounted on fully adjustable feet. To provide the water movement required, it can be connected to most power head pumps up to 500 gph. capacity, or to the injection pump of some protein skimmers, or to the suction line of many canister filters.