This handy filter will do the same job economically and quickly. These fish, especially bettas, generally do not like violent currents, they prefer calm and steady water. This filter has been designed to have a slow current which will easily allow bettas, goldfish discus, dwarf cichlids, rockfish and krill fish, to continue to breed and spawn comfortably. This will encourage them to continue breeding and spawning comfortably. At the same time, the sponge filter provides a home for the fish's food, supplementing their daily dietary dose or food intake. When used alone it is ideal for a 10.5 gallon tank ---- It only requires an air pump and airline tubing (sold separately) to work. This will produce many tiny air bubbles to increase oxygen flow. Simply attach the air pump to the top center of the filter and place it into the tank. Please note that the base of this silent filter is weightless, so you may need to weigh it down. It is suitable for tanks up to 10.5 gallons in size. Use 2 or more filters in larger tanks. Easy to clean and reuse ------ This low cost sponge filter can be used many times. It can be cleaned with water from the tank instead of tap water when it is time to change the water. Simply rinse and squeeze a few times until you see water coming out of the sponge.