You add a beautiful piece of driftwood to your tank and within a few days it grows a white, fuzzy or slimy coating. Some keepers describe it as cotton candy, others as jelly. It can look alarming, especially if you were not expecting it.
This is one of the most common experiences in aquarium keeping. This guide explains what is generally thought to cause it, whether you need to worry, how to deal with it, and how to prepare new wood to reduce it next time.
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What is the white fuzz?
New driftwood carries sugars and other organic compounds near its surface. Once submerged, these leach out and feed fast-growing bacteria and fungi that form a visible biofilm. It is often described as one of the following:
- White, fluffy or cottony growth that sways in the current
- Clear to white jelly that sticks to the wood
- Thin white strands concentrated on cut ends or soft spots
It is commonly reported on many wood types, including mopani, spiderwood, and Malaysian driftwood, and on cholla and branch-style woods. Woods with more exposed fresh surface or soft spots tend to show more.
Is it harmful?
In the vast majority of tanks, no. It is a natural biofilm that consumes organics from the wood and fades on its own. Many keepers leave it and simply wait.
- If ammonia or nitrite reads above zero, the decaying growth may be adding to the load. Siphon some off and do a water change.
- If the wood smells strongly rotten or feels mushy, it may be decomposing. Remove and inspect it.
- If the growth spreads onto plants, fish or other decor rather than staying on the wood, treat it as a different problem and investigate.
- If fish show signs of illness, consult a reputable care sheet or an aquatic veterinarian rather than assuming it is the wood.
How long it lasts
Most keepers see it peak within the first week or two and disappear within a few weeks. Some pieces have a second, smaller flush. It typically does not return once the wood has been in the tank for a while.
| Stage | Typical timing | What you might see |
|---|---|---|
| Appears | First few days | Thin white film or fluff, often on cut ends |
| Peaks | Around the first one to two weeks | Thicker cottony coat; may look worse before better |
| Fades | Over the following few weeks | Patches shrink and disappear |
Timing varies by wood type, size, water temperature and how much the wood was prepped.
How to remove it
- Siphon it off during a water change. Hover the gravel vacuum just above the wood to lift loose growth.
- Brush it with a soft toothbrush reserved for the aquarium. Brush toward the siphon so fragments are removed.
- For removable pieces, take the wood out, scrub under running water, and return it.
- Repeat as needed. Each removal takes some of its food source with it.
Do not use bleach, soap, or household cleaners on driftwood that goes back into the tank. Do not dose algae or fungus treatments for this; it is unnecessary and may harm livestock and plants.
Animals that graze it
Many tank residents eat the fuzz readily:
- Nerite, ramshorn and mystery snails
- Cherry and Amano shrimp
- Bristlenose plecos and other wood-grazing fish
- Otocinclus in established tanks
Only add animals to a cycled tank, and choose them for their long-term fit. See freshwater cleanup crews and our pleco size guide.
Prepping driftwood to reduce fuzz
Preparation will not always prevent fuzz, but it often reduces it and also helps with tannins and floating.
Scrub
Scrub with a stiff brush under running water to remove loose bark, soft spots and debris.
Soak
Soak in a bucket or tub of water for days to weeks, changing the water regularly. This leaches tannins and organics. Many keepers soak until the water stays fairly clear.
Boil (if it fits)
Boiling smaller pieces helps release organics and tannins, can help waterlogged wood sink sooner, and helps sanitize it. Boil in a large pot for a period, let it cool, and repeat if needed. Large pieces can be done in sections or treated with repeated hot-water soaks.
| Method | Helps with fuzz | Helps with tannins | Helps with floating |
|---|---|---|---|
| Scrubbing | Some | A little | No |
| Long soak | Yes | Yes | Yes, over time |
| Boiling | Yes | Yes | Yes, often faster |
Other things new driftwood does
White fuzz is not the only surprise new wood brings. Knowing what else to expect helps you separate normal settling-in from real problems.
Tannins and tea-colored water
Many woods release tannins that tint the water yellow or brown. This is generally harmless to most fish, and some keepers seek it out for blackwater setups; see blackwater and biotope tanks. If you prefer clear water, keep soaking the wood before use, and run activated carbon or a purpose-made organics-removing resin in your filter. Regular water changes also reduce the tint over time.
Floating
Dry driftwood often floats at first. Options include soaking until waterlogged, boiling, weighing it down with aquarium-safe rock, or attaching it to a slate base with aquarium-safe screws or ties. Some keepers wedge it under other hardscape until it sinks on its own.
Small pH shifts
Tannins can lower pH slightly, mostly in soft water with low KH. In water with moderate buffering the effect is usually minor. Test pH and KH if you are adding a lot of wood to a small tank.
Soft or crumbling patches
A little surface softening on bark edges is normal. Wood that becomes spongy, smells sour, or starts to fall apart may be decaying and should be removed.
A checklist for adding new driftwood
- Scrub away loose bark and debris
- Soak, changing the water regularly, until it sinks and the water is reasonably clear
- Boil smaller pieces if they fit in a pot
- Check for soft or rotten spots before placing
- Expect white fuzz in the first weeks and plan to siphon it
- Test ammonia during the first few weeks, especially in small tanks
Buying and collecting driftwood safely
- Buy driftwood sold for aquarium use when possible.
- Avoid treated, painted or varnished wood.
- Avoid soft woods with resin (like pine) and anything that has been near chemicals.
- If collecting your own, research which woods are considered aquarium-safe from reputable sources, and check local rules about collecting.
- Inspect for soft, rotten or mushy areas before use.
Our list of tank-safe driftwood and hardscape covers common options, and our guide on testing hardscape safety covers rock.
FAQ
Is the white fuzz on driftwood dangerous to fish?
It is generally considered harmless and fades within a few weeks. Keep testing ammonia and remove it by siphoning if it builds up heavily.
How long does white fungus on driftwood last?
Most keepers see it appear within days, peak within a week or two, and fade over the following few weeks.
Should I take the driftwood out?
Usually not. You can siphon or brush the growth off in place. Remove the wood only if it smells rotten, feels mushy, or you want to scrub it outside the tank.
Does boiling driftwood prevent white fuzz?
Boiling and soaking often reduce it by removing organics, but they may not prevent it entirely. It is a normal step in new wood settling in.
The bottom line
White fuzz on new driftwood is a common, usually harmless phase. Siphon or brush it off if it bothers you, let grazers help, and keep an eye on ammonia. Soak and boil future pieces to reduce it. In a few weeks the wood will settle in and the fuzz will be gone. Find more hardscape and setup guides on the AquariumSetup blog.