White Fuzz on Aquarium Plants – Common Causes and Treatments

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If you have a tank with any type of plants in it, then there is a good chance that you will eventually experience some sort of white fuzz growing on them. This happens because aquariums are an environment where light, food, and water can be scarce. In order to survive in this environment, algae and other types of fuzz produce spores that allow them to stay alive for as long as possible until their environment changes or becomes more suitable.

Interesting as this may be, it can also become a nuisance if you are not aware of what is going on. This article will identify some common types of fuzz that grow on plants in tanks and explain how to solve the problem they cause

What Causes White Fuzz On Aquatic Plants?

Various aquarium plants with fishes

The first part of this article explores some possible causes of white fuzz that can grow on aquatic plants. We will take a look at what this fuzz is, why it occurs, and how to solve the problem that it causes.

Once we have done so, it is also worth looking at some other causes of white fuzz in aquariums as a whole. It is important to be aware of these causes because if you are not, then it is likely that they will cause other problems in your aquarium too.

With that being said, let’s take a look at what causes white fuzz on aquatic plants!


The number one culprit of white fuzz on aquatic plants is diatoms. These are a type of algae that use silica to protect themselves from the environment in which they live, much like how our skin protects us here on Earth.

Because diatoms come in a wide range of colors such as brown, white, and red, many people often confuse them for other types of algae. They are typically caused by unbalanced water chemistry in the tank. Once they are identified, their disappearance often goes hand in hand with an improvement of aquarium water conditions.

One way to tell if it is diatoms you are dealing with in your tank is by looking closely at the plants that have fuzz growing on them. If there are many small bubbles all over, then you are likely dealing with diatoms.

The Solution: 

To remove diatoms from your plants and tank, you need to do a thorough cleaning of the glass on the outside as well as inside. Make sure that when doing this there is no residual soap left in the tank because it will kill any fish or plants if it gets into their environment.

After thoroughly cleaning all visible parts of your aquarium with water only (no soap), you will need to use an aquarium safe conditioner that contains Acriflavin. This is a type of medicine, so be careful when using it because even in small amounts it can prove harmful if not properly diluted.

Repeat this cleaning process every three days until the diatoms are completely removed from your tank.

White Algae

Among the many kinds of algae that are known to grow on water plants, white algae are perhaps the most common. It can be identified by its white, cotton-like appearance that often feels rough to the touch. Unlike diatoms, this type does not use silica and instead attaches itself to the plant using a root-like structure called rhizoids.

While there are many similarities between white fuzz caused by diatoms and that caused by growths from white algae, there are also many differences. For instance, white algae can be easily pulled off a plant, whereas diatoms are much more difficult to remove.

In addition, the fuzz caused by white algae will change color based on the lighting in your tank and how well it can photosynthesize. Therefore, this type of white fuzz can sometimes look like green algae, especially if the lighting is poor.

The Solution: 

The first thing you should do if you notice a growing population of fuzz algae on your plants or decorations is to improve water conditions in the tank. This can be done by doing a water change of at least 50% and cleaning the filter. This step is also important if you intend to add algae-eating fish such as Siamese algae eaters or dwarf shrimp species to your tank as a way to help their aquarium stay clean.

Once you have done this, clean your tank’s filter regularly and scrape algae off decorations that are hard to remove using other methods. You can do so by using a toothbrush and regular aquarium-safe soap. Many hobbyists also report success with using a razor blade to clean the filter and decorations.

Something else you can consider is adding driftwood into aquariums. There are many benefits of driftwood, but the main reason people use it is its ability to help keep white algae at bay. This is due to the fact that tannins can leach out of a driftwood surface, which has the effect of lowering pH levels in the water. Once this happens, algae has a very hard time surviving in the tank.

Aquatic Moss

Another type of plant that might cause white fuzz to grow on your aquarium plants is moss. Though moss is typically green in color, it can take on a whitish appearance if they are not getting enough light.

Common speckled mosses that can cause this type of fuzz to grow on your plants include Java moss, Christmas moss, and Taiwan Moss. They will grow on the aquarium plants in a similar way that diatoms and algae do, creating a white layer on top of them.

Aquatic moss flourishes in tanks with poor lighting and can prove to be difficult for plant owners to remove. However, if you keep the moss regularly pruned it will not grow as fast or produce enough fuzz to overwhelm your plants.

The Solution: 

One of the best things that you can do in order to deal with an infestation of this type is by pruning the moss and adding more light to your tank. You can prune aquatic moss by removing any loose pieces from the surface of your plant leaves and cutting it into smaller chunks. This can be done by using a pair of scissors that have been cleaned with aquarium-safe soap beforehand.

To add more light, you should try to increase exposure in small increments over time until you see positive results. You can do this by placing the aquarium near a window or adding more light fixtures to your tank. Opt for fluorescent or LED lights, as these are the best choices for plants. Once you have done so, you should start to see results within a few weeks or months.

By following these steps outlined above, you should be able to eliminate most of the white fuzz caused by algae in your tank. However, in some cases, white fuzz can be caused by other factors. The following conditions are more likely to affect fish, but it’s also worth learning about them as they can affect the overall health of your aquarium.

White Fuzz In Aquariums – Other Possible Causes

As previously mentioned, white fuzz doesn’t just affect aquarium plants. Any time you notice white cotton-like stuff in your fish tank, you should be concerned and do everything you can to figure out what it is. Whether the condition affects your plants, fish, or even just the aquarium water itself, here are some of the most common causes.


One of the more well-known types of diseases is called ich (pronounced like sick). This parasitic infection is caused by the protozoan Ichthyophthirius multifiliis. Typically caused by poor water conditions, ich affects the fish’s skin, causing white fuzz to form on its body and fins. However, this isn’t always visible to the naked eye – some types of ich will appear as small white spots that are lighter than the rest.

Fish that are affected by ich will usually show symptoms within a week or so of becoming infected. To make it easier to spot, keep an eye on your pet for signs such as lethargy, loss of appetite, clamped fins, the growth of small white spots (which could be ich), and the appearance of small white fuzz on their body or fins.

Left untreated, ich can result in death. Thankfully, this severe condition is highly preventable. All you need to do is ensure your tank has optimal water conditions and that the temperature of the water doesn’t go below 70° Fahrenheit. For most tropical species, the optimal range is between 75 and 80° Fahrenheit.

The Solution: 

To remedy the situation, try adding aquarium salt to a separate tank. The recommended amount to add is two tablespoons of salt per five gallons of water. Then, transfer your fish into the tank and allow it to swim around in the salt bath for about thirty minutes. Do note that the salt bath technique should not be used on scaleless fish, as they can easily get irritated and harmed by the salt.

This method is effective in killing off most types of Ich, but if it does not work for you, there are other options available. One option you can try is adding potassium permanganate or acriflavine into your fish tank. You will need to follow any instructions on the product label carefully, as these chemicals can be harmful.

Once you have administered these chemicals, it’s important to keep an eye on fish activity throughout the day. If you notice any of them have stopped eating, stop treatment immediately and do your best to improve water conditions in the tank. You may also need to consider adjusting your levels of salt or medication, as this can affect how well the treatment works.


White fuzz on fish can also be caused by a bacterial infection, most commonly columnaris (often referred to as cotton-mouth disease). A bacterium called Flexibacter causes this condition, which is why it’s sometimes known as “flex.” Fish housed in a dirty tank is particularly susceptible to columnaris as nutrient imbalances and fish waste allow the Flexibacter bacterium to thrive.

The main symptom of columnaris is white fuzz on the outside or lips of an infected fish – this can sometimes appear as a cottony growth. Other symptoms include red wounds around the mouth area or fins that have been eroded away by scratching against rocks in the tank. Like most bacteria in fish, severe infections are highly contagious and can lead to death

To prevent this condition, keep your tank water clean and maintain an ideal water temperature. Never overcrowd your tank – there’s a reason why environments with an abundance of fish (such as farms) are often prone to infections. When the waste of fish becomes too much for their environment to handle, it can lead to disease.

The Solution: 

Time is of the essence when it comes to treating columnaris, so you should take action at the earliest sign of infection. As was the case with ich, using the salt bath method is effective against columnaris. You will need to add about two tablespoons of salt into a separate tank and allow your pet to swim around for up to thirty minutes.

Investing in an aquarium water treatment kit can be a great way to ensure your tank remains clean and disease-free. This will include medications such as NovAqua, which can help eliminate toxins in the water caused by uneaten food or fish waste – two things that encourage bacterial growth like columnaris.

If you don’t see any improvement, try using a different medication such as potassium permanganate or acriflavine. If neither of these treatments works, you can try to administer antibiotics into your tank (e.g., Maracyn). The downside of this method is that it often takes several days for your fish to recover completely, so be patient!

Fungal Infections

In some cases, white fuzz on fish may be the result of a fungal infection. Fungal infections are less common than bacterial infections because your aquarium water needs to contain high levels of ammonia and nitrate for fungi to thrive.

However, once these conditions have been met, it’s possible that fungus spores can invade a susceptible fish – this is most common in goldfish and angelfish that have been stressed by water temperature changes or poor aquarium conditions.

The main symptom of a fungal infection is redness, which can be accompanied by a white fungus (this will appear as cotton-like growths around the mouth and gills). Other symptoms include lethargy, loss of appetite, and weight loss.

The Solution: 

The best way to prevent fungus from attacking your fish is to keep their environment as clean as possible. Use a water tester kit to ensure your ammonia and nitrate levels are between 0.25 ppm to 0.50 ppm, as this will make it difficult for fungus spores to survive in the water.

It’s also a good idea to clean your tank with hot water once a fungal infection has been confirmed. This will “shock” the fungus and stop it from spreading further, but be aware that this method cannot always guarantee a successful result. If you don’t see any improvement after cleaning your tank with hot water (e.g., two to three times in one week), then consider using an anti-fungal medication such as methylene blue or acriflavine, which you can buy online at Amazon.

Those opting for a pet that can keep their tanks clean should invest in voracious fungus eaters such as Amano shrimp and some species of loaches. These relentless fungus-eating fish and shrimp will feed on any fungus they come across, so you can also try adding one or two to your tank if there’s a lot of fungal growth in it.


White fuzz is unsightly at best and dangerous at worst, so it’s important to act quickly if you spot any signs of growth on your plants or fish. If you follow the tips and suggestions above, you can almost guarantee that your tank will stay clean and healthy for years to come.

We hope you found this article helpful! As usual, please feel free to ask us any questions or share your own experiences in the comments section below. We love hearing from our readers, and this would really make our day! Also, if you know anyone who is struggling with white fuzz on their plants or fish, please share this article with them. Sharing is caring!

Wanda is a second-generation aquarist from the sunny tropics of Malaysia. She has been helping her father with his freshwater tanks since she was a toddler, and has fallen in love with the hobby ever since. A perpetual nomad, Wanda does her best to integrate fish-keeping with her lifestyle, and has taken care of fish in three different continents. She loves how it provides a nice break from the hustle and bustle of life.

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