Last update: November 3, 2022

White Algae in An Aquarium – Causes & How to Get Rid

How to Remove White Algae in An Aquarium?

White algae can be annoying in an aquarium. Sure, these common tank algae are not dangerous for your fish, but they develop and spread quickly.

These algae look like a web with a slick film. They usually don’t grow on glass, but they can grow on driftwood, rocks, or decorations.

Luckily, you can get rid of white algae, and if you know what causes them in the first place, you can prevent them from growing in the future. 

In this article, we explain all the possible causes of white algae in an aquarium and how to get rid of them.

Causes For White Algae 

There could be several reasons for white algae invasion in your fish tank.

The first most common cause of invasion can be bad water circulation. This can often happen in new tank setups, as the water takes time to regulate.

The algae invasion could also be because of bad filtration or a lack of it. So make sure your tank has all the tools it needs to make it function properly and smoothly.

The lighting conditions could also cause this, and you can find a more in-depth explanation in the lighting section below. But, if your tank has natural light and/or has too much light per day, it can be bad for your tank population and promotes algae growth.

Usually, nine hours of light is enough for a fish tank. This means that you can easily prevent white algae or any other type of algae from appearing.

The final cause for white algae in aquariums is when your fish tank is overcrowded. So don’t keep too many decorative items in your tank, and make sure it’s big enough.

There could be other causes for white algae, but these are the most common ones. However, do not hesitate to speak with a specialist if you find that these causes don’t apply to your white algae invasion case.

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How To Get Rid Of White Algae In My Tank

Now for the most important part of this article and the one you’re waiting for. How exactly do you get rid of white algae in your tank?

If, unfortunately, you can’t prevent white algae (check the sections below to see how to do that), you’ll have to remove these algae as soon as possible.

The first thing you need to do is to determine what caused this white algae invasion so it doesn’t happen again, this helps you know which method to pick to best tackle it. 

Usually, it’s because of a level of nutrients that’s way too high. That often happens in new tank setups, especially in smaller ones. So you can measure the nutrient levels and adjust accordingly.

Then, you can perform several water changes, but make sure your tank population is cared for, as even small changes can upset them.

Overfeeding My Aquarium Pets

Most new fish owners want to make sure that they feed their aquarium pets enough which is why they often end up overfeeding them.

You should avoid this at all costs, especially if you have a small aquarium. Not only can it make your fish, snails, shrimps, crabs, or other creatures sick, but it also dirties your tank.

Then, you have food residue in your aquarium, which makes the water and the tank’s glass dirty. As you can imagine, this is bad for your tank population, as it can mess with the tank’s water conditions and visibility.

Most importantly, overfeeding your aquarium pets can lead to white algae or other algae types. 

So what can you do to fix this problem? First of all, stop overfeeding your tank population. Next step is to maintain a clean tank and perform regular changes. You might also want to invest in a good filter and even a water pump if the CO2 levels are too low.

You can learn the different feeding techniques in the fishkeeping world, especially because different pet species have different needs. Also, remove any food residue after you feed your tank population.

In tougher white algae cases, you need to add aquarium-safe chemicals to your tanks. Just do your research before using them, as some can kill your fish and damage your tank.

Of course, another great and natural way to get rid of some white algae is by adding algae-eating fish or snails in your tank, for example. It’s also really entertaining to watch a cleanup crew clean your tank!

Too Much Lighting

As mentioned previously, too much lighting and inappropriate water settings in your aquarium can cause white algae to appear in your tank and any other type of algae.

You can reduce the lighting for your fish tank, and the hours it’s on. Also, you could get some aquarium plants for your tank to outcompete the white algae and absorb more of the light. 

Just make sure the plants are adapted to your aquarium environment and its population. It’s also best to quarantine them before you introduce them, as they could be contaminated.

As you can see, it’s easy to get the right lighting for your aquarium, which will help control white algae growth.

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Upgrade Your Aquarium Filter

Another thing you might want to do to avoid white algae in your aquarium or get rid of it is to upgrade your aquarium filter. And yes, it makes a huge difference.

For example, you can update your aquarium’s water pump and have a really high-quality filter. This helps you to have a regular water cycle, as well as increase the speed of the flow, if necessary.

The same goes if you’re using a mechanical filtration system instead.

If your filter can’t remove accumulated waste products quickly enough, you are at a high risk of getting white algae in your tank. 

It’s an investment to upgrade your aquarium filter, and we realize that. But we promise you it’s a good thing to do. It saves you countless months of trying to get rid of white algae and saves you so much work in general. Plus, your tank population will thank you!

Keep The Tank Clean

This is pretty self explanatory and logical. If you don’t want any invasions, particularly white algae ones, you have to keep your tank clean.

So remove any organic food waste after you feed your aquarium population, and avoid overfeeding. Also, you should rinse food and any additional residues.

Obviously, don’t leave any dead plants, dead fish, or other dead things in your fish tank.

Keeping your tank clean also includes having tank equipment that actually works and is up-to-date. 

The last thing you can do to keep your aquarium clean and avoid white algae is to perform water changes. Ideally, these should be weekly.

Prevent any changes in water and tank conditions, as they should be kept as regular as possible, to avoid white algae and also to keep your tank population happy and healthy.


Here is an FAQ so you can find out even more information about white algae and all the answers the other potential questions you might have.

How much time does it take to remove white algae?

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Unfortunately, it can be difficult to get rid of white algae invasions, as they’re hard to control. So it takes time and patience.

We can’t predict an exact amount of time, as this depends on each tank, how you maintain it,  and how severe the white algae invasion is. 

So it’s essential you do everything to prevent an algae invasion in the first place and that you are aware of all the possible causes for white algae growth.

Removing these algae can take a few weeks or even months. And it might take a few tries as well.

Don’t get frustrated. You’ll get there at some point. The more you know about white algae, the less time it should take.

What is the white fuzzy stuff in my fish tank?

If you notice white fuzzy stuff that looks a bit like cotton in your fish tank, it’s not white algae. So what is it exactly?

Well, it’s usually a sign that there is an infection in your aquarium. It could either be a bacterial fungus or it could also be fungus.

This infection can actually be dangerous for your fish, so you need to treat it immediately. A water treatment kit usually does the trick. Also, you can prevent this if you know what can cause it.

Common reasons for these parasites or fungus include:

  • Irregular/poor water temperature:

You can easily fix this by progressively changing your tank’s water cycles. Also, keep on top of your aquarium’s maintenance. Perform weekly water changes and regularly control the water settings, as well as the nutrients level in it.

  • Dirty tank and unmanaged fish tank:

This goes in hand with the previous reason, but keep your tank clean to avoid any infections. Plus, your fish will be happier and healthier!

  • Overfeeding and organic food waste:

This is pretty self-explanatory. If you overfeed your fish, it’s not only not good for their health, but it leaves food residue in the tank, which dirties the fish tank and promotes the growth of bacteria, fungus, and algae.

  • Ill fish that could have a bacterial infection or fin rot

To avoid this, you can quarantine every new fish you get, especially if you don’t know where it comes from exactly.

What fish will eat white algae?

Keeping algae eaters in your aquarium, not all necessarily fish, is a great way to remove algae invasions, to keep your tank clean and also to add more life to your tank.

Different kinds of fish, snails, and shrimp will eat different types of algae.

Here are some tank recommendations to help you control your white algae population. Just remember to research every species before you insert them into your tank, as they might not be compatible with other tank mates or might have specific requirements for their care.

Fish that like to eat white algae include Siamese algae eaters, Barbs, Mollies, American Flagship, Danios, and Chinese algae eaters. As for snail recommendations, Sun snails or Nerite snails are good ones.

What is white mold?

White mold is a type of fungus that’s very dangerous for your fish, and can create eye infections, swim bladders, digestion problems, and other health issues.

So it’s essential you do everything to prevent it and that you remove it as soon as you spot it. A fungus treatment usually does the trick. Remove any eggs with tweezers and add methylene blue on them before.

Usually, what causes white mold is poor water conditions, overfeeding your fish, fish waste, or even wood decorations.

You can easily prevent white mold if you don’t overfeed your fish, keep your tank clean and with regulated water conditions, and quarantine any decorations before you add them to your aquarium.

Does white algae mean my tank is cycled?

New tanks take time to have a full cycle and reach their full maturity. White algae and any other types of algae can mean that your tank is cycled.

That’s because algae thrive on high nutrient levels.

However, you shouldn’t keep white algae in your tank, as it spreads quickly and dirties your tank, even if they don’t hurt your fish.

So you can either add more plants to outcompete your white algae, add algae-eating fish and maintain a clean tank with stable water conditions. You can measure the nutrient levels and adjust them accordingly, so they’re not too high.

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Does dead algae turn white?

Yes, dead algae can turn white, but it can also turn grey. Then, it progressively falls. So you can remove it safely.

Final Thoughts

It’s pretty easy to get rid of white algae in an aquarium, but it’s time-consuming. 

The best thing you can do to avoid this is to know the causes so you can prevent an invasion in the future.

Ian Sterling

I've been keeping fish for over 30 years and currently have 4 different aquariums – it's an addiction. I'm here to teach you everything there is to know about fishkeeping.

I also use this site as an excuse to spend lots of money on testing and reviewing different aquarium products! You can find my reviews here.

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