Driftwood

 These tannins create a slightly acidic environment that helps to keep viruses and disease-causing bacteria at bay. The tannins released can also increase available oxygen in the water column, further stimulating your fishes' immune systems.
Helps buffer and maintain lower pH in tank

Promotes fishes' natural behavior: Adding driftwood to an aquarium can help promote the natural behavior of your fish. Driftwood exists in almost every river or lake, so naturally, your fish will be attracted to it. Your fish will use it for hiding, breeding, or even as food.