Understanding Biofilm on Aquarium Wood: What It Is & Why It's Nothing to Fear!

So you have just created a beautiful aquascape using let's say Red moor root and a few days later BAM Slimy white stuff!  If you've recently added wood to your aquarium, you might have noticed a slimy, white or clear fuzz forming on the surface. Don’t panic this isn’t a sign that something’s gone wrong. In fact, what you're seeing is a natural process known as biofilm.

What Is Biofilm?

Biofilm is a thin, often slimy layer of microorganisms, primarily bacteria and fungi that colonise surfaces submerged in water. When you place organic materials like driftwood into an aquarium, they provide the perfect surface and nutrients for these microorganisms to thrive.

Typically, this biofilm appears as a whitish, cloudy, or stringy slime that can seem unsightly at first. But looks can be deceiving, it’s not harmful and plays an important role in the ecosystem of your tank.

Why Does Biofilm Appear on Wood?

Biofilm forms as a result of the natural breakdown of organic matter in this case, the cellulose and tannins in the wood. When you place driftwood into an aquarium, it begins to leach out natural compounds. These compounds attract beneficial bacteria and fungi, which begin to colonize the surface and form biofilm.

This is especially common with newer pieces of wood or in recently set-up tanks. Over time, as the nutrients on the wood surface are consumed and microbial populations stabilize, biofilm often disappears on its own.

Is Biofilm In The Aquarium Dangerous?

No, biofilm is completely safe and natural. It’s a sign that your aquarium is cycling and developing a healthy microbial balance. In fact, the bacteria and fungi in biofilm can aid in breaking down waste and maintaining water quality.

That said, while biofilm itself is harmless, an excess buildup can be a cosmetic issue or contribute slightly to cloudy water if disturbed. It could also swarm plants and mosses attached to the wood, In such cases, you can remove it manually by gently scrubbing the wood followed by a water change.

What Eats Biofilm In The Aquarium?

Nature has its own cleanup crew! Many aquatic creatures find biofilm a delicious snack. Some common aquarium inhabitants that love to graze on biofilm include:

• Shrimp (especially Amano, Cherry, Crystal red shrimp)

• Otocinclus catfish

• Plecos (especially smaller species like Bristlenose)

• Snails (such as Nerite, Clithon Snails)

• Certain livebearers (like guppies and Endlers) may nibble at it occasionally

These animals help manage biofilm naturally while adding activity and interest to your tank. Please make sure you do not add clean up crew too early your tank must still be cycled before adding them, although biofilm is more than likely to appear first which is where maintenance comes in whilst you wait to add your clean up crew. 

Should I Remove Biofilm?

In most cases, no. It usually disappears on its own after a few weeks as the tank matures. However, if the appearance bothers you, it's swarming plant attached to wood or it starts floating around, you can:

• Use a turkey baster or siphon to remove loose bits

• Gently scrub the wood under tank water during maintenance

• Introduce more biofilm-eating clean up crew once tank is cycled 

In Summary

Biofilm on aquarium wood might look alarming, but it’s a natural and even beneficial part of establishing a healthy aquatic environment. With a bit of patience and help from your tank's cleanup crew, it will usually fade away, leaving your driftwood looking clean and your aquarium thriving.

Embrace the fuzz! It’s just another step in building a balanced, beautiful aquarium.