Can I Use Oak Wood in Aquarium? What Types of Wood Are Safe to Use?

Your fish swim around a relatively empty tank. You have a piece of wood you found in a nearby creek, stream, or river, but you’re not sure if it’s safe to put into the aquarium so your fish have a little more variety in their living space.

Generally speaking, many hardwoods are safe to use. Coniferous wood like pine or cedar, and some others, are not, however.

Great care should be taken not to harm your fish by introducing a harmful type of wood to the environment. The wrong wood can essentially poison your fish and may even kill them if left for too long. The right wood, on the other hand, enhances the visual appeal of your tank while providing a more vibrant environment for your fish.

Can I Use Oak Wood in an Aquarium?

Oak is known for being a safe wood for use in aquariums. It is also easy to find and identify in many areas, so it’s a good place to start if you’re wanting a nice do-it-yourself addition to your tank. Oak still has to be treated before use, however, so be sure to follow the steps outlined later on to ensure its safety for your fish.

Can You Use Any Wood in an Aquarium?

You may be wondering, “What kinds of wood are safe for aquariums?” While many types of wood are harmful, a little bit of digging yields an impressive list of beautiful woods that are perfectly safe for your fish tank.

What Kind of Driftwood Is Safe for Aquariums?

There are many types of native wood that are perfectly safe to use in your aquarium with the proper preparation. Be sure to select a piece of wood from this list to ensure that a piece you select will be safe for your fish.

Safe woods for aquariums include:

  • Alder: Alder is a group of deciduous shrubs/trees in the birch family distributed widely across North and some areas of South and Central America.
  • Apple: Applewood can be found near orchards in many areas of the country.
  • Cherry: Like apple trees, cherry trees are often cultivated but wild cherry trees can be found worldwide.
  • Hawthorn: Hawthorn is another large shrub/tree family that comprises a few hundred species native to temperate areas of the northern hemisphere, such as Europe, North America, and Asia
  • Beech: Another temperate northern hemisphere native, beechwood is durable and resistant to abrasion.
  • Heather: Known for growing near oak.
  • Oak: Oak is one of the most commonly encountered trees in the US, and is widely distributed throughout the northern hemisphere.
  • Sycamore: A wide-canopied deciduous tree, the American Sycamore is widely distributed and easy to forage for.
  • Pear: Another fruit tree whose wood may be used.

What Kind of Wood Is NOT Safe for Aquariums?

Some woods are highly unsafe for your fish and should be avoided at all costs. They can introduce toxic chemicals to the tank’s water and poison your fish. Sometimes this is due to chemicals called tannins that are released into the water over time that lower the pH, while others are directly toxic to fish.

These unsafe woods include:

  • Cedar and other coniferous trees
  • Cypress
  • Grapevine
  • Horse Chestnut
  • Walnut
  • Yew
  • Lilac
  • Ivy

What Are Tannins?

Tannins are chemicals produced by plants that are present in many kinds of wood. Tannins are important biomolecule when in the live plant, binding to proteins and performing various functions. Putting driftwood into a tank without properly cleaning it first will allow tannins to leach into your tank’s water.

This discolors the water (stains it yellowish or brownish) and lowers the pH as well. Dissolved tannins may also give your water an unpleasant odor.

You can resolve this issue by changing the water in your tank and removing the contaminating piece of wood. If you change your water regularly, you may not even notice tannin build-up, especially after a few months of introducing a new piece of driftwood. Carbon filters will also help remove tannins that build up in your tank.

Are Tannins Bad for Fish?

Tannins are not directly harmful to fish, but their presence may cause less than ideal conditions if left unattended. By lowering the pH of the water, tannins can be harmful to some fish over time. On the other hand, tropical fish (namely those from South America) may benefit from the soft water conditions. Some aquarium keepers take advantage of this to facilitate proper conditions for their fish.

Will Driftwood Rot in An Aquarium?

But won’t my found piece of driftwood rot in my aquarium? That’s how wood works, right? You expose it to water and it breaks down over time. While this is true, there are steps you can take to preserve the wood and slow this process significantly. Be sure to clean any driftwood you select with great care and soak it thoroughly to avoid faster rotting.

How Do You Make Wood Safe to Use in Aquariums?

So how do you make wood safe for your fish? Preserving your driftwood will increase the longevity of the wood and kill any bugs or bacteria. Without doing so you risk hurting your fish. Aso, make sure to remove algae from the driftwood from time to time.

So be sure to follow the following instructions closely.


  1. Scrub your wood: Get off all dirty and other organic materials before soaking with a stiff scrub brush. Leaving these particles on will speed the degradation of your wood.
  2. Submerge your driftwood in distilled water: You can use a rock or brick as a weight to hold it down or use a lidded container to ensure a complete soaking.
  3. Soak for two weeks: Change out the water regularly as it becomes dark with leached tannins.
  4. Dry in an area of low humidity: Be sure your wood is completely dry before using.

Final Thoughts

Many types of easily found wood would make a beautiful addition to your fish tank. While some are toxic to fish or release high levels of tannins into the water. With the proper preparation, you could save some money on a nice addition to your aquarium while having a fun project to work on in your spare time.

Proper preparation is key because the tannins in wood can hurt your fish and should be leached out before adding to a fish tank. Under no circumstances should you use bleached wood in an aquarium, however. This can be hazardous to the health of your fish as well.

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