The pieces of wood that have been preserved look very attractive in my planted aquariums and give them a special character. As others have pointed out, the wood leaches the tannins into the water for quite a while, giving it various tea tones. How dark the tea's appearance will depend on how much you can pull out before sticking the piece of wood into the aquarium. I simmered and simmered small pieces all day, changing the water in between, until the "tea brew" was significantly clearer. I put a large piece, too big to put in a kettle, in a new water-filled bin and left it in the sun for a couple of weeks and it was worth the extra effort. Any tannins that were still in the wood were eventually absorbed by the charcoal in my filters when I added pieces of driftwood to my aquariums. They say that tanning agents do not harm the fish and in my case they are absolutely right. My fish didn't seem to mind the temporarily colored water at all, but the aquarium water would be quite dark if I didn't boil and/or soak the pieces first.
π AquaticHI 27-Inch Aquarium Tongs - 100% Reef Safe - Multi-Purpose for Fresh & Saltwater Fish Tanks - Clip Plants, Spot Feed Fish & Coral - Keep Hands Dry
9 Review
π³ Hygger Betta Log: Resin Hollow Tree Trunk Ornament for Betta Fish Tank Decor, Wood House Aquarium Accessories
9 Review
Faucet for kitchen (sink) Blanco Fontas II (granite) pearl
16 Review
18lb BLQH Aquarium Gravel River Rock with Pebbles Stones β Natural Polished Decorative Gravel for Garden Landscaping and Ornamental Rocks in Mixed Colors
12 Review
Efficient 2-In-1 Magnetic Fish Tank Cleaner With Non-Slip Design And Scratch-Free Blades
37 Review
Mini pump Xiaomi Mijia Electric Pump 1S, plastic, black
55 Review
π U-BCOO Aquarium Gravel Cleaner Fish Tank: Manual Siphon for Efficient Filter Gravel Cleaning and Water Change in Tanks
22 Review
𧲠Efficient Magnetic Fish Tank Cleaner: KEDSUM Floating Clean Brush with Handle Design
34 Review