How to make aquarium wood sink is one of the most common questions we’re asked by fishkeepers setting up a new aquarium — and if your wood is floating, don’t worry. This is completely normal.
At Birchwood Aquatic Centre in Swanley, we help customers from across Kent choose, prepare, and position aquarium wood safely. Below, we explain why aquarium wood floats, how to make it sink properly, and what to avoid.
Most aquarium wood — including bogwood, driftwood, mopani, and spiderwood — floats at first because air is trapped inside its natural fibres.
Until that air is slowly replaced by water:
This doesn’t mean the wood is faulty or unsafe — even premium, hand-selected pieces behave this way initially.
Soaking allows the wood to naturally become waterlogged over time.
How to do it:
Typical soaking times:
The water may turn brown — this is caused by tannins and is completely normal.
If you want to scape your tank straight away:
Over time, the wood will sink naturally and the weights can often be removed.
For aquascaping or planted tanks:
This keeps layouts stable and prevents movement long-term.
Boiling smaller pieces can:
However, large pieces may not fit in a pot and some woods can crack. If unsure, soaking is the safer option.
Avoid these common mistakes:
Metal can rust and chemicals can harm fish — always use aquarium-safe methods.
Floating wood itself isn’t harmful, but unsecured pieces can:
That’s why it’s important to secure wood properly before adding livestock.
Tannins released from aquarium wood:
Species such as tetras, rasboras, angelfish, plecos, and bettas often thrive in tannin-rich water.
If you prefer clearer water:
It can be tempting to use driftwood or wood collected from nature, but this is one of the most common causes of unexplained fish losses.
Natural wood can:
Aquarium-safe wood is chosen specifically because it’s non-toxic, stable, and suitable for long-term submersion.
If you’re unsure whether a piece of wood is safe, don’t risk it — ask before adding it to your tank.
