Congo Wood is a more dense type of wood that we offer. It significantly contributes to the overall health of your aquarium ecosystem and livestock. As Congo Wood gradually releases tannins, it can slightly lower pH levels and create a more natural, blackwater environment that many fish species prefer. Congo Wood also supports beneficial bacteria growth, which is essential for maintaining water quality. With beneficial bacteria growth, congo wood will also produce biofilm which many aquatic pets will feed on such as shrimp and snails. With Congo Wood, you're not just adding décor to your tank, but also fostering a healthier, more dynamic ecosystem for your aquatic life.