Driftwood has to be dead... really dead or it will rot in the aquarium. Driftwood has been dead for a long time, in some cases a hundred years or more. All toxins and volatile chemicals from the wood are gone at that point and real driftwood has great water-carved lines and shapes. If you don't want to buy pricey driftwood at a store, you can try ebay or just go to a clean beach or lake and pick some off the ground.