diftwood is best picked off a beach so that the wood has been sitting in the sun bleaching it out, not any peice of wood will do. it has to be dried! and Dead!! you can just cut of a limb of a tree and expect it not to kill of everything in your tank! Somonas is right, you can get it under water, just make sure you clean it well, and bleach it out, leave it out in the sun for a few weeks, then boil it and pop it in the tank..