Driftwood preparation means boiling, soaking, and testing before it goes in the tank

Raw driftwood pulled from a beach or riverbed will leach tannins into your water, cloud it brown, and may carry bacteria or parasites. You need to boil it to kill organisms and remove surface debris, then soak it for days or weeks to draw out the tannins that discolour the water. The wood is ready when the soak water stays clear and the wood sinks on its own — untreated driftwood floats for months.

The whole process takes one to four weeks depending on the wood's size and density. You cannot skip steps or rush it; wood that still releases tannins will stain your tank and alter pH. Start with wood that is already dead and weathered — fresh wood or wood from living trees will rot quickly in the tank.

Key Takeaways

  • Boil driftwood for 15 to 30 minutes per inch of thickness to kill bacteria, parasites, and surface algae spores.
  • Soak the wood in fresh water for one to four weeks, changing the water every two to three days, until the soak water stays clear.
  • Test the wood by placing it in the tank — it should sink when ready; if it floats, it needs more soaking time.
  • Use only dead, weathered wood from beaches or rivers; avoid wood from living trees or treated lumber, which will decay or poison the tank.

Boiling the driftwood to kill organisms

Fill a large pot with water and bring it to a rolling boil. Submerge the driftwood completely — if it is too large for one pot, cut it into pieces or use a bathtub with a heating element. Boil for 15 to 30 minutes per inch of thickness. A piece one inch thick needs 15 minutes; a three-inch piece needs 45 minutes.

Boiling kills bacteria, parasites, and the spores of algae and fungi that may be living on the surface. It also begins to soften the wood and open its pores, which helps tannins leach out later. After boiling, remove the wood with tongs and let it cool on a clean surface. Do not pour the boiling water down a drain if the wood is very dirty — let the sediment settle first and pour off the clear water.

Soaking to remove tannins and test for sinking

Place the cooled wood in a bucket, basin, or aquarium filled with fresh water. Use dechlorinated water if you have it, but tap water works. The wood will release brown tannins into the water almost when ready. Change the water every two to three days. Each time you change it, the water will be less brown. After one to two weeks, the water may stay nearly clear between changes — but continue soaking for at least another week to be certain.

The soak time depends on the wood's density and size. Soft, porous wood may be ready in one week; dense hardwood can take three to four weeks. You will know the wood is ready when you soak it for two or three days and the water stays clear. At that point, place the wood in a bucket of fresh water — if it sinks when ready, it is ready for the tank. If it floats, it still contains air pockets and needs more soaking time.

Choosing the right driftwood to start with

Use only dead, weathered wood from beaches, rivers, or lakeshores. This wood has already lost its bark and outer layers, and the interior is dense enough to sink eventually. Avoid wood from living trees, freshly cut wood, or branches still attached to trees — these contain sap and will rot quickly in the tank, fouling the water.

Do not use treated lumber, painted wood, or wood that has been stained or sealed. These contain chemicals that will leach into the water and harm fish. Avoid wood that smells strongly of chemicals or has visible mould or soft rot — soft rot will continue to break down in the tank and cloud the water. If the wood crumbles when you press it with a fingernail, it is too far decayed to use.

Anchoring driftwood so it stays in place

Even after soaking, some driftwood will still float slightly or shift in the current. You can anchor it by tying it to a rock or piece of slate with fishing line or plant weights. Tie the line around the wood and the anchor point — use knots that will not slip. Fishing line is nearly invisible in the tank; plant weights are small metal or ceramic anchors sold at aquarium stores.

Alternatively, you can bury one end of the wood under substrate (gravel or sand) so it cannot move. This works best for wood with a flat or blunt end. Make sure the substrate is deep enough that the wood will not shift if a fish digs nearby. If you are using live plants, you can tie them to the driftwood with fishing line once it is in place — the plants' roots will eventually anchor themselves to the wood.

Testing water chemistry after adding driftwood

Even after thorough soaking, driftwood can still lower pH slightly and release trace tannins. Test your water with a pH kit or test strips one day after adding the wood, then again after one week. Most aquarium fish tolerate a small pH drop, but if your tank is already acidic or you keep fish that need neutral to alkaline water, monitor closely.

If the water becomes noticeably brown or the pH drops more than 0.5 points, remove the wood and soak it longer. If the water stays clear and pH is stable, the wood is fine. Over time, the wood will stop affecting chemistry as it fully stabilizes in the tank. You can also use activated carbon in your filter to remove any remaining tannins if discolouration bothers you, though brown water is harmless to most fish.

Preventing algae and mould on driftwood

Driftwood in an aquarium will eventually grow algae and sometimes a white or grey fuzzy coating called biofilm. Biofilm is harmless — it is actually beneficial because it provides food for some fish and shrimp. Algae growth depends on light and nutrients; if your tank has high light and high nitrates, algae will grow faster.

You can control algae by reducing light to 8 to 10 hours per day, keeping nitrates low through water changes, and adding algae-eating fish or shrimp like plecos, otocinclus, or Amano shrimp. Do not scrub the driftwood aggressively — the biofilm and light algae coating actually protect the wood and look natural. If algae becomes thick and unsightly, a soft brush or old toothbrush will remove it without damaging the wood.

Frequently Asked Questions

How long does driftwood take to sink on its own?

Untreated driftwood floats for weeks to months depending on density and size. Boiling and soaking speed this up to one to four weeks total. If you need the wood to sink when ready, anchor it with fishing line or bury it in substrate rather than waiting.

Can I use driftwood from my backyard or a local stream?

Yes, if it is dead and weathered. Avoid wood from living trees or wood that is still green inside. Boil and soak any wood you collect outdoors to remove bacteria, parasites, and tannins before putting it in the tank.

Will driftwood hurt my fish?

Properly prepared driftwood will not hurt fish. The tannins it releases are harmless — they just discolour the water. Unprepared wood may carry bacteria or parasites, which is why boiling is important. Once the wood is in the tank, monitor pH and water colour for the first week.

What if my driftwood still floats after weeks of soaking?

Some very light or porous wood will never sink fully. Anchor it with fishing line tied to a rock, or bury one end under gravel. Alternatively, you can use it as a decoration above the water line or in a terrarium instead of an aquarium.

Can I speed up the soaking process?

Boiling longer helps, but you cannot safely skip the soaking step. Changing the soak water daily instead of every two to three days may shorten the process slightly, but the wood still needs time to release tannins fully. Rushing this step means brown water in your tank.