Sizes vary from 6" - 12" please specify which size you would prefer. Not only does driftwood look great, but it also stimulates and maintains the ecosystem within an aquarium. Much like the substrate and filter media in an aquarium, driftwood promotes the growth of beneficial bacteria. These bacteria are very important as they break down fish by-products into less toxic compounds, keeping your fish healthy. The added surface area of driftwood ensures that you'll always have a healthy colony of these bacteria. Your fish wall also use this to breed, hide and some will even eat it.