For convenience and quiet, choose a Tetra Whisper 30-60 Internal Power Filter. These Tetra Whisper Aquarium Filters mount on the inside of the aquarium, rather than hanging from the outside, making it possible to place the tank flush against a wall. These 30-60 Tetra Whisper Power Filters are unusually quiet, since the motor is under the water. Offering the same quality and performance as an external filter, the Tetra Whisper 30-60 Power Filter will function in as little as two inches of water, allowing it to be used for turtle tanks or for creating a waterfall inside the tank. Tetra???s Bio Foam eliminates toxic ammonia and nitrate that are not healthy for fish. Designed for aquariums up to 30 -gallons, the Tetra Whisper Aquarium Filter features adjust easily to high or low water levels with mounting suction cups and/or brackets. Each Tetra Whisper 30-60 Gallon Filter comes with one pre-assembled whisper filter cartridge.