Blackwood is very similar to Malaysian driftwood. Blackwood is the root section of blackwood trees in Malaysia. They contain dark colors with black streaks and have a high density, allowing it to easily sink in your aquarium. 4” - 7” Natural Blackwood Driftwood. This wood is Naturally Heavy and dense so Usually sinks Directly. Every piece is unique and made by nature. See pictures. Some wood may need to soak a few hours, days before it fully sinks. Tannins from the wood Tints aquarium water a beautiful and natural amber shade, Helping reduce pH, soften and create a more natural Blackwater Biotope. Pre Soaking or Boiling will reduce tannins. Great for all kinds of aquariums, terrariums and reptiles. Fish, Shrimp, Lizards, Bugs and any and all small critters you keep will enjoy it providing a more natural habitat. Don't forget you can Attach plants and mosses to the wood. Not only for your critters, You can use it as natural decoration, for arts & crafts, air plant holder or anything else you can imagine. Sustainably harvested and collected. Some driftwood can develop a white biofilm after being submerged. The biofilm is not harmful and will be eaten by fish, shrimp and snails. Some types of plecos will eat driftwood as part of their natural diet.