How to Remove Surface Scum and Keep Your Aquarium Healthy
Have you ever looked at your aquarium and noticed a thin, oily layer floating at the top of the water? This common problem is known as biofilm or surface scum. Not only does it spoil the look of your tank, but it can also affect the health of your fish especially in nano aquariums.
In this guide, we’ll explain what causes biofilm, why it can be harmful, and how tools like a surface skimmer can solve the problem.
What Is Biofilm in an Aquarium?
Biofilm is a layer of proteins, oils, and organic waste that builds up on the water surface. It often appears in aquariums where:
- Fish food or fertilisers are breaking down
- Dead plant matter is left to decay
- Natural bacteria produce organic by-products
While biofilm might seem harmless, it actually prevents proper gas exchange. This means less oxygen enters the water, while CO₂ can build up.
Why Surface Scum Is a Problem
Leaving surface scum untreated can:
- Block oxygen from reaching the water
- Trap excess CO₂, leading to unstable water chemistry
- Reduce water clarity and make your aquarium look unclean
For nano tank owners, biofilm can build up quickly and cause problems much faster than in larger aquariums.
How to Remove Biofilm in Your Aquarium
There are several effective ways to get rid of biofilm and prevent it from coming back:
1. Manual Removal
A temporary fix is to use a paper towel to soak up the oily film. While easy, this only provides short-term results.
2. Improve Water Movement
Biofilm forms most often in areas with low circulation. Adjusting your filter outlet or adding a small water pump will help break up the scum and improve oxygen levels.
3. Use a Surface Skimmer
The most reliable solution is investing in a surface skimmer. These devices continuously pull water from the surface, removing biofilm and surface scum before it can build up. This keeps your aquarium water crystal clear and ensures healthy oxygen exchange.
For larger setups, a protein skimmer is also a great choice. It removes dissolved organics before they form surface scum, keeping the tank balanced.
4. Maintain Good Aquarium Habits
- Avoid overfeeding fish
- Perform regular water changes
- Clean your filter regularly
The Best Long-Term Fix
If you’ve ever asked, “Why is there an oily layer on my tank’s surface?” the answer is biofilm. While it’s common, it shouldn’t be ignored. The best long-term solution is an aquarium surface skimmer, which keeps your water clear, your fish healthy, and your tank looking beautiful.
