How to Get Rid of Brown Spots on Amazon Sword [3 Reasons]

Growing aquatic plants is an art and the grower is an artist. But this art needs the artist to be very careful and observant as well. This is because the aquatic plants are grown on stones and soil submerged in water and they depend on various substrates which tend to worsen with time.

Sadly any kind of deviation in the tank environment can cause big trouble. And the Amazon swords in your tank can also be victim to it. These plants get brown spots all over the leaves due to 3 very common reasons which are – 

  • Lack of nutrients
  • Too much light and 
  • Presence of excess brown algae. 

However, the good news is you have nothing to panic about, after noticing brown spots on your aquatic plants.

Because this article will give you an overall idea of how to care for your Amazon swords as well as a step-by-step planting guide. That’s why stick to reading through the whole article so that you can provide your plants with a healthy and nutritious environment all the time.

So, let’s get this show on the road–

Why Do Amazon Swords Have Brown Spots?

Amazon Sword Brown Spots

1. Lack of Nutrients

Amazon swords are heavy feeders so they take up quite a good amount of nutrients through their roots if their leaves are getting brown spots that means they are not getting enough substrates for their growth and development. 

Control Measure

In this case, you have to get them some root tabs immediately to help them have healthy growth. And then observe for a few days and you will be able to see the difference. And after getting their required dose of nutrients the Amazon swords will have vigorous growth filling a large part of your tank. (Our Pick: API LEAF ZONE Freshwater Aquarium Plant Fertilizer)

The leaves that have brown spots are very unlikely to repair so it is best if you cut off the dead and brown-spotted parts of the leaves to make your tank look more attractive. This will also encourage new growth. 

2. Too Much Light

We know that all plants need enough hours of light to make food for themselves. But they don’t feel very good if exposed to an excessive amount of light. This results in damage to many plant cells. If this is the case in your tank then your Amazon swords will be deprived of making enough food and this will result in brown spots in them.

Control Measure

You have to add CO2 in different forms to help the plants become strong and thrive. You can use bio-available organic carbon along with other root tabs together.

And remember to reduce the amount of lighting you provide. Don’t keep them turned on all the time. It’s best if you keep them on for 6 hours every day. You can use LED light for a better result in your aquatic plants.  

Another important thing is to place the plants in such a way that the light can reach equally to all of your plants without blocking one another.

3. Excess Brown Algae

It’s another problem that is caused by too little exposure to lights in the tank. The thing is if your tank has a very low light system then it will promote the growth of brown algae. And we know that all plants need CO2 to produce food for themselves. 

So, if the tank is filled with algae, it will consume all the CO2 and nutrients from the tank. As a result of this, the Amazon sword plants will develop brown spots on their leaves. 

You will be able to detect the brown algae by seeing the tank water get cloudy and the glass of your tank will look dirty.

Control Measure

Though we call them brown algae, they are not true algae. They are actually one kind of microscopic pest called diatoms. 

And the issue here is, these things get settled on your tank and make it look ugly. But the good news is you can easily wipe them off from the glass with a piece of cloth. Swiftly clean the whole area from top to bottom. If you do the sweeps haphazardly the brown algae can spread in clean areas from the previous dirty part. 

And to prevent the growth of brown algae you have to keep your tank water free from nitrate and silicates. That means you have to stop overfeeding. Because they love to grow in the presence of these nutrients. This is why it’s best to always fill your tank with distilled or filtered water and use an algae eater. (Our Pick: API ALGAEFIX Algae Control)

In case you need to plant new Amazon sword runners then here is the step-by-step guide–

How To Plant Amazon Swords Like An Expert

Amazon Swords Planting
  1. Before starting to plant them make sure your tank water is fresh and within the right pH range that is between 6.5 to 7.5. You can use a pH testing kit specially made for aquariums (our pick: VIVOSUN pH and TDS Meter Combo)
  2. If the pH is low then increase it by using alkaline materials If the pH is too high than the range you can apply some acidic substrates.
  3. And use these substrates by following the product’s instructions. Because the wrong pH can be fatal to plants and fishes. 
  4. Now you have to get the right temperature for them. It’s best to keep the temperature between 72° to 82° F (22° to 28° C). Always use a thermometer to check the temperature of your aquarium on a regular basis. 
  5.  You can use an automatic and suitable aquarium heater that will regulate the temperature of the tank.
  6. If the water needs to be cooled down then you can shade the glass with a screen so that it doesn’t get sunlight through the window.
  7. The next step is to make sure your tank is getting 7 hours of light every day, especially during the time of establishment. Otherwise, the Amazon swords can gradually wilt and even die.
  8. Now, you have to enrich the tank with enough nutrients, especially iron and potassium to let your plants thrive. You can either use any liquid plant food or any root tab products.
  9. Then you have to dig out a small hole in the aquarium soil deep enough to cover the roots of your plant. And place the Amazon swords and plant them by covering them with the dug-up soil. 
  10. Press a little with some pressure to bury the roots deep enough to prevent the plants from floating in the water.  
  11. Always plant them on the background or corner of the aquarium otherwise their foliage will block the view as well as lights.
  12. The Amazon plants tend to grow very large and block the lights in the tank. So if you don’t have a big aquarium then prune them off with the help of shears.

Frequently Asked Questions (FAQs)

Does The Amazon Sword Need To Be Submerged?

Since the Amazon swords are aquatic plants they need to be fully or partially submerged in the water. In addition, these plants will need a required range of pH in the water and temperature. And a proper level of light will help it to thrive.

Are Amazon Swords Hardy?

They are pretty hardy and this is why the Amazon swords are super popular as aquarium plants. It usually needs only a little amount of care and grows vigorously once it has established itself in the tank.

Do Amazon Sword Plants Bloom?

Amazon sword plants grow very slowly and after a certain time, it grows a branch in length that comes out of water in search of light. And some beautiful and tiny white flowers are produced during any time of the period from May to September.


Amazon swords are amazing aquatic plants that justify their name by the swordlike structure of the leaves. But they look very ugly and dirty when they get brown spots on their leaves. And to keep the beauty of your aquarium you have to take proper actions at the right time. Otherwise, even your fish along with your plants can be affected due to this unhealthy environment in the tank.

Provide proper nutrients in enough amounts and regulate the lighting hours of the tank. And don’t forget to clean the tank from time to time. I hope the information in this article helped you to have a better insight into how to get rid of brown spots on your Amazon sword plants. 

Howard Parker

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