Why Are My Aquarium Plants Turning Brown? Potential Causes & Solutions

It’s always a great idea to add some plants to your fish tank as they improve the aesthetic of the tank while boosting the water quality.

Aquarium plants getting brown is one of the most commonly encountered challenges people experience. As a novice aquarist, you may wonder: Why are my aquarium plants turning brown?

Look no further than this post! It will show you the potential causes and solutions to solve this problem. Let’s scroll down!

Why Are My Aquarium Plants Turning Brown?

Many issues may happen in your tank, causing annoyance or making it tough to maintain the tank environment.

Among them, the aquarium botanical garden turning brown may be a mystery for many new aquarists as it manifests differently.

Below is the list of potential causes for this phenomenon and ways to prevent it from worsening in the future. Let’s keep reading!

Plants Do Not Get Enough Nutrients

The most common cause of aquarium plants becoming brown is a deficiency of nutrients. They may even perish in some situations.

Your water may be low in a variety of macronutrients and micro.

Underwater, botanical gardens require magnesium, potassium, nitrogen, and phosphorus. Without these substances, they can’t survive and grow.

Lack of nutrients may cause a variety of symptoms. Plant turning brown is the most common one.

However, you may notice your plant turn yellow and black when it begins to rot.

A plant with low phosphorus, for example, may shrink and acquire dark brown blotches.

Furthermore, most plants don’t require many micronutrients. But if you don’t give them enough, they may succumb to necrosis.


Adding fertilizers to your aquarium after changing the tank water is the most outstanding technique to ensure your botanical garden doesn’t get hungry.

aquatic plant

Plants Do Not Get Enough Fertilizer

If you use aquarium plant fertilizer, ensure there isn’t too little or too much in your tank.

For instance, excess nitrate may cause algae growth or deplete oxygen levels.

The botanical garden will perish as a result of this since they require particular elements in the tank water to survive.

If your tank water has excess plant fertilizers, remove part of it by changing the water weekly.

On the other hand, the plant may not receive insufficient fertilizer. As a result, it may get wither and have dark brown spots.


Ensure that the aquarium botanical garden gets adequate fertilizer or substrate to thrive.

Plants Do Not Get Enough Lighting

Lack of light is also a typical cause of browning plant leaves. New plant owners may also give overlighting to the botanical garden.

Plants will turn brown if they don’t get enough light. Your plant will not survive in its watery setting if it doesn’t provide enough light.

Insufficient light may also cause brown algae to grow in the botanical garden. The water and plants will become unhealthy due to the algae bloom.


Make sure your aquarium lights and light arrangement are sufficient for your botanical garden.

Plants Do Not Get Enough CO2

Carbon dioxide is the most common source of carbon for the botanical garden because it is a central aspect of photosynthesis.

The aquarium plant’s leaves may turn brown when it does not receive enough Carbon dioxide (CO2).


Use aquarium equipment or yeast to boost the CO2 level in the tank. Check this equipment for any symptoms of malfunction regularly.

If you are a newbie aquarist, this video may be helpful for you:


Plants Are Overcrowded.

Another cause plants become brown is a lack of space for their root systems to expand.

It is true for aquarium botanical gardens grown on the tank substrate. The tank substrate shrinks with time, leaving less space for the botanical garden to flourish.

This case can also occur if a tank contains too many plants simultaneously.

When plant roots become stuck together, their capacity to receive oxygen and nutrients suffers.


If the rhizomes of plants get congested, separate them using aquarium scissors.

This method will give the aquarium botanical garden more space to develop while preventing its leaves from turning brown.

Substrate Isn’t Suitable For Plants.

Substrate refers to the sand bed in which your botanical garden will develop. It acts as the topsoil for a plant in a pot.

When you put plants in the improper substrate, their roots will rot and die. Your fish may get poisoned if they accidentally eat a dead plant.


When adding any new plant to a tank, it’s best to place them in a container with appropriate water or substrate for them to develop.

The Water in Your Tank Isn’t Clean.

You can’t expect the botanical garden to remain in good health if the water in the tank isn’t clean.

In the water, fish produce a variety of waste and contaminants. A botanical garden can aid in neutralizing this issue to some extent.

However, the botanical garden can’t balance the condition when there are excess toxins and nitrates in the water.

They may begin to droop and grow sick when there is too much pollution in a fish tank.


Adjust water parameters to make sure the water is fresh enough for the botanical garden to grow in.

You can consider using aquarium devices like a heater or filter to improve the water condition.

Other Common Problems With Aquarium Plants

Apart from this issue mentioned above, your aquarium botanical garden may encounter other common problems, including

  • The leaves turn yellow: Potassium deficiency and sufficient light make the leaves turn yellow.
  • The leaves turn white: Carbon dioxide, iron, and nitrogen deficiency will cause this situation.
  • They disintegrate: An abrupt shift in the water’s properties like pH level or temperature leads to this issue.
  • They turn transparent: Iron deficiency and insufficient illumination are the causes of leaves becoming translucent.
  • They have brown spots: Brown algae grows on the leaves if the light isn’t bright enough.

Wrapping Up

This article eventually solved your headache: why are my aquarium plants turning brown?

There are various reasons behind this common issue. Nutrient deficiency, insufficient lighting, or poor water condition are the leading causes.

We have recommended the most practical solutions so that you can have prompt treatments for your lovely aquarium botanical garden.

If you have further questions, you can leave a comment below to let us know.

Thanks for taking the time to read this post!