Mopane Congo Driftwood Medium (10-15")A handsome, dense driftwood piece similar to Pacific Driftwood, but with much more interesting texture. These are a must have for shrimp tanks, as they provide shelter for breeding, edible bio films, and wonderful tannins in the water as they break down. They are also useful as a Ph buffer in quantities. Untreated Mopane (also called Mopani and Congo wood) will eventually break down in the aquarium. This is a completely desirable and natural process,