Oxygen Plus Bio-Filter 7

Easy-to use biological filter for tropical aquarium fishAquarium filter sponge for efficient biological filtrationGreat biological filter for breeding or spawning aquariumsThese filters allow you to cultivate nitrifying bacteria for superb biological filtration. Great for fry aquariums and brine shrimp hatcheries because they prevent young fry from being trapped in the filter media. Operates silently, creating numerous minute bubbles for increased oxygen flow. Each requires an air pump and airline tubing, sold separately. Oxygen Plus Bio-Filter 6 measures 4-3/4" x 9-7/16" high and is for aquariums up to 110 gallons. Oxygen Plus Bio-Filter 7 measures 4-1/2" 7-1/4" high and is for aquariums up to 50 gallons.