Without doubt the most commonly used type of aquarium wood anywhere in the world. Bogwood is wood that has been preserved by the anaerobic conditions of these environments over hundreds if not thousands of years in a bog. It is discoloured by the tannins found in the bog over this lengthy period.It comes in many shapes and sizes and is often used as an attractive natural looking ornament in the aquarium. Other benefits include providing hiding places for reclusive species, helping form natural boundaries for territorial species and it can be used as an anchor point for attaching aquarium plants such as Java Moss, Java Fern and Anubias barteri, further improving the aesthetic appeal of your tank.Bogwood contains tannins (organic material) that will leach into your water giving it a tea coloured and stained colouration. This is perfectly harmless. In fact some aquarists even find it desirable when trying to recreate Amazonian black water conditions etc. Unfortunately there is no way to be sure how much tannin a piece of bogwood will leach or how long it will continue to leach it for.