Zoo Med Mopani Wood - Aquatic SmallZoo Med's Mopani Wood is a beautiful, two color African hardwood for aquariums. The smooth surface, textured detail, and unique mottled color adds interest and enrichment to habitats. All natural wood leaches tannins, which discolor water and reduce pH levels. To minimize this effect, soak wood in a separate container, and change water daily to remove excess tannins. The wood will be ready when the water color goes from dark brown to a very light.