Ideal for breeding, isolating, or acclimatizing fish and shrimp, the Fluval Breeding Box serves as a safe and secure nursery for livebearer fish. Its space-saving, hang on design easily mounts to the exterior of your aquarium allowing for easy viewing and maintenance. With the use of an air pump (1L / minute) and airline tubing, the warm, oxygenated water from your aquarium flows continuously through the breeding box (air pump and tubing sold separately). Once born, fish fry slip through the v-shaped divider and become safely segregated from adults. As the breeding box uses your existing aquarium's water, no additional heaters or filters are required. Comes in a medium size.