Why do my aquarium plants turn brown? learn to overcome (2023)

I'm a fan of planted tanks and started my first planted tank in 2013. They can elevate your tank's visual appeal to a level that no other items can.

I have to admit that keeping live plants is relatively more challenging than just keeping fish from experience. But I never gave up. I was passionate about vegetation and learned to care for it through experience, study and research.

I often get a common question across different platforms; Why are my aquarium plants turning brown? Aquarium plants are sensitive to water conditions. If the state of the aquarium water deteriorates, the plants give the first warning sign that something is wrong.

Plants need a balanced mix of light, CO2 and other nutrients.The main causes of brown discolored aquarium plants are listed below..

  • Lack of necessary nutrients.
  • insufficient lighting
  • CO2Lack
  • presence of brown algae
  • unsuitable terrain
  • bad water condition
  • wrong way to plant

Content Show

The main reason why aquarium plants turn brown

When plants start to turn brown, it is an indication of disease and nutrient deficiency. Plants require light and CO2 for the process of photosynthesis, which is essential for their growth and survival.

Photosynthesis is a photochemical reaction that takes place in the green leaves of a plant. Through this process, plants produce sugar and oxygen from light and CO2, which become the source of energy for their survival.

Other nutrients like nitrogen, phosphate, potassium, magnesium, iron and manganese are also essential for healthy aquarium plant life. Plants absorb these nutrients from the aquarium water and substrate mainly through their leaves and roots.

A balanced supply of all of the above elements is the key to healthy plants. Any imperfections (deficiency or excess) can cause the plants to turn pale and brown. I will discuss everything individually.

Why do my aquarium plants turn brown? learn to overcome (1)

1) Inadequate lighting

As I said before, lighting is one of the basic needs for a plant to survive. It is the source of your energy. When we absorb carbohydrates from food, plants produce sugars through photosynthesis. If the light is dim, the plants will certainly starve.

Have different aquarium plantsdifferent lighting requirements. Fast growing plants usually require more energy to grow and therefore need bright lighting.

Slow growing plants like Anubias, Java Fern, Marimo Ball, etc. require less. But more or less all aquarium plants need light. And when it's not enough, they suffer from vigor and vitality, causing them to turn brown.

Symptoms of light deficiency:

  1. Plant growth becomes slow or does not grow at all.
  2. Mature leaves turn yellow or brown.
  3. The entire plant turns pale, white or transparent.

Insufficient light reduction:

Why do my aquarium plants turn brown? learn to overcome (2)
  • Ensure full spectrum lighting:

Plants receive sunlight in the wild, but indoor aquariums are sunlight limited. Although direct sunlight is not advisable for aquariums as it encouragesuncontrolled algae growth. A full-spectrum lighting system is the best solution for providing sufficient light for planted aquariums.

  • Use efficient LED lights:

Nowadays,LED aquarium lights are readily availablein the market. LED lights are reliable and cheaper. As long as they provide the necessary spectrum, the plants will thrive.

  • Know the needs of your plant:

As I said earlier, each plant's need level is not the same. You need to know your installation requirements. But everywhere1.5 watts of LED lighting per gallon is the minimum requirement for planted tanks with dimly lit plants. For light-intensive plants, the rule of thumb is 3 watts of light per gallon..

  • Keep plants that require little light:

While this reduces plant selection, low-light plants are hardy and more pleasant to care for. If you're a beginner, I suggest keeping plants in low light (like Anubias, Java Fern, Java Moss, Marimo Ball, Dwarf Rotala, etc.)

2) CO2 deficiency

Then comes CO2, another essential element for the photosynthetic process. So plants suffer from the same consequence of lack of light. CO2 is naturally present in aquarium water to some extent.

Plants in low light can do well with the natural CO2 in the aquarium water. But if your tank is stocked with a lot of fastidious plants, CO2 can become limiting and the plants will starve. They turn brown and pale as death.

(Video) Why Your Aquarium Plants are Turning Brown and What To Do

Why do my aquarium plants turn brown? learn to overcome (3)

Symptoms of CO2 deficiency:

  1. Tiny vegetation.
  2. The leaves turn brown and yellow.
  3. The stems turn brown and lead to the death of the plant.

Reduction of CO2 deficiency:

  • Select undemanding plants:

The plant's CO2 requirement is directly related to its light needs. So if you choose low light plants they will use less CO2.

  • Keep a day-night rhythm:

Plants consume CO2 and produce sugar and oxygen in the presence of light. But in the dark shereproduce CO2 from oxygen and sugarthrough breathing

Turning off the lights at night helps to increase CO2 levels from fish and plant respiration.

  • Use a CO2 injection system:

By adding CO2 to aquarium water, you can increase CO2 levels. You need to install aCO2 system to inject CO2sou Aquarienfresser.

A standard CO2 injection system consists of a CO2 cylinder,CO2 rules, diffuser, bubble counter, needle valve and some other optional accessories.

  • Reduce water circulation flow:

If the recirculation flow of the water in the tank is too high and it forms too many bubbles, the dissolved CO2 will evaporate from the water. Therefore, reducing the turbulence of the aquarium water is another way to keep the CO2 dissolved in the water.

Risks related to high levels of CO2

High CO2 content in the aquariumwater can be fatal for your fish. Therefore, especially when using a CO2 supplementation system, dosing rate control is crucial.

Very demanding plants do well with a CO2 content of 30 mg/l. However, the safe level for fish is less than 35 mg/l of dissolved CO2. In addition, fish show signs of stress and lethargy.They lose their appetite, become weak and may die.

Why do my aquarium plants turn brown? learn to overcome (4)

3) Lack of other nutrients

In addition to light and CO2, there are some essential nutrients for plants to help them grow and stay healthy. Aquarium plants absorb these nutrients from the aquarium water and substrate.

Some of these nutrients are macronutrients and plants need them in abundance. Nitrogen, phosphate, potassium and magnesium are macronutrients.

Plants also need a certain amount of iron and manganese, and they are micronutrients. You need a balanced amount of macronutrients and micronutrients. Both nutrient deficiency and excess can cause problems.

Why do my aquarium plants turn brown? learn to overcome (5)


Nitrogen is a vital nutrient for all types of plants, including the vegetation in your aquarium. Aquarium plants collect nitrogen in the form of nitrate, nitrite and ammonia compounds. In this way, they reduce nitrate, nitrite and ammonia in the aquarium water and make the fish healthy.

In a full tankIdeally, there should be no ammonia or nitrite. Therefore, the main source of nitrogen in aquarium plants is nitrates dissolved in water.

Symptoms of Nitrogen Deficiency

  1. New leaves appear crisp and reddish.
  2. Mature leaves turn brown.
  3. The leaves start to fall.
  4. Slow growth.

Excess nitrate and ammonia

Nitrogen compounds are essential for plant growth but toxic to fish. If ammonia builds up in a tank, it indicates that the tank is not fully circulating; or the nitrogen cycle is disturbed in some way.

Nitrate buildup is a common problem in aquariums, even in planted aquariums. If aquarium plants cannot fully absorb the produced nitrate, the content increases. Changing the water is the solution for the above cases. Otherwise, it will stress or even kill your fish.

Too much nitrate in aquarium water can also promote algae growth.

How to overcome problems related to nitrogen

(Video) 5 Ways to SAVE Melting Aquarium Plants Before It's Too Late

The key is to maintain a balanced level of nitrate (5-10 mg/l) in the planted tanks. If the nitrate level in a recirculating tank drops to zero, it indicates that the plants are consuming too much. And they're probably fully booked.

Areduce nitrite levels, run regularlywater change.

Why do my aquarium plants turn brown? learn to overcome (6)


Phosphate is an essential nutrient for aquarium plants. Phosphate compounds naturally occur in aquarium water from many sources, including decaying plant matter, fish waste and food scraps.

Prepared fish foods and organic salts also add phosphate to the aquarium water. A lack of phosphate causes a number of problems for aquarium plants.


  1. holes in the leaves.
  2. Brown spots on the leaves.
  3. The new leaves are starting to turn yellow.

Symptoms of Excess Phosphate

  1. The leaves of the plants begin to turn dark brown to black.
  2. Excess algae begins to grow in the aquarium water.

How to overcome phosphate problems

If you notice symptoms of phosphate deficiency, add phosphate-rich fertilizer and organic salt to the aquarium water.

For excess phosphate problems, perform water changes and a thorough cleaning of the substrate.

Related reading:The best fertilizer to provide nutrients to plants.


Potassium is one of the most important plant nutrients naturally occurring in aquarium water. Plants use a lot of potassium to grow and thrive. So this inadequacy stresses her out a lot.

Potassium deficiency symptoms

  1. The pinhole begins to form on the leaves.
  2. The edges of the leaves turn pale and yellow.

How to overcome potassium problems

Keep water in good condition by balancing pH, hardness and CO2 levels. Potassium supplementation is also helpful.

Why do my aquarium plants turn brown? learn to overcome (7)


Magnesium is a vital nutrient for the maintenance of your vegetation. Magnesium and iron are essential for a plant's bright green color. While magnesium deficiency reduces the plant's ability to absorb iron. Therefore, they are connected.

Symptoms of Magnesium Deficiency

  1. Leaves begin to turn brown with brown and yellow spots.

How to overcome magnesium problems

Fertilization and nutrient-rich soil can solve this problem.


Iron is an essential nutrient for the bright green color of plants. Iron salts can be present in tap water, but all forms of iron compounds are not soluble. Plants can only absorb soluble iron compounds from aquarium water. Therefore, iron deficiency is a common problem.

Why do my aquarium plants turn brown? learn to overcome (8)

Iron deficiency symptoms

  1. The leaves of the plants begin to lose their green color and become pale, yellow and discolored.
  2. Young leaves grow white and pale.
  3. The leaves and stem tissues become necrotic, resulting in death.

How to overcome iron deficiency

(Video) My Aquarium Plants are Turning Brown?

Iron is difficult to absorb from water. So, providing anutrient-rich substrateIt is the best solution to overcome iron deficiency.


Plants don't need manganese in large amounts, but it's important. Mainly, it helps plant metabolism to use other nutrients effectively and grow.

Manganese deficiency symptoms

  1. Plants become weaker and their growth slows down.
  2. The leaves of the plants begin to turn yellow to brown.
  3. It begins to form holes in the leaves.

overcome manganese deficiency

Iron-rich substrates and fertilizers contain traces of manganese and can supplement it.

Why do my aquarium plants turn brown? learn to overcome (9)

Other reasons why aquarium plants turn brown

brown algae

Aquarium plants can sometimes turn brown due to algae formation. Brown algae can form a layer on green plants. Occurs mainly in partially cycled tanks. A lack of nutrients doesn't always have to be the reason for a brown plant.

Brown algae is not as harmful as nutrient deficiencies, and mitigation is relatively less painful. Do regular water changes. I hope the problem is fixed.

bad water condition

Plants can absorb some water contaminants, but not all. Significantly undissolved contaminants can seriously affect water quality. Therefore, poor water quality can be one of the main reasons behind vegetation loss of your plants.

When tap water contains undissolved iron components, it can cause plant leaves to turn brown. Likewise, dirt and debris can cause the same thing.

Effective mechanical filtration is the key to keeping aquarium water free of undissolved solids. Perform regular water changes, which is very beneficial to ensure the health of fish and plants.

Why do my aquarium plants turn brown? learn to overcome (10)

unsuitable terrain

Substrate is a crucial aspect of a planted aquarium, as most aquarium plants get their nutrients from the substrate. A suitable mineral-rich substrate can encourage your plants to thrive.

Mineral-rich soils are my first preference in planted aquariums. but I triedgrowing plants in gravel, and it works for many plants. While a sandy substrate is not suitable for most aquarium plants.

Choosing the wrong substrate for your plants could be a possible reason why your plants turn brown and die.

wrong planting

You've heard the saying "What you sow, you will reap". The way you planted your aquarium plants makes your future foundation for healthy growth.

Each type of plant has a unique planting technique. you have to be surePlant aquarium plants correctly. For example, some plant roots must go deep into the soil, while others must not go deep. Some aquatic plants do not have roots, but have prehensile organs such as rhizoids. They also need another special planting method.

If planting is not enough, the plants cannot take root and grow; Instead, they turn brown and die.

Other problems related to aquarium plants

  • holes in the leaves

The possible cause of the formation of holes in the leaves of aquarium plants is a lack of potassium and phosphate. First black dots appear, then visible holes.

  • slow growth

Slow growth can be the result of all kinds of deficiencies. Insufficient light, CO2 and insufficient nutrition can retard the expected growth of your aquarium plants.

  • brittle leaves

If you notice brittle leaves on your aquarium plants, the pH of the water is probably too high. Check the pH and if it is below 7.5 then the possible reason could be something else.

Iron and potassium deficiencies can also cause plant leaves to become brittle.

  • black leaves

Poor water conditions and excessive iron contamination in the water can be responsible for the development of black leaves on aquarium plants. Changing the water is the solution to end it.

common questions

How do I get rid of brown algae on my aquarium plants?

The main reason for this is the higher levels of nitrate and phosphate in the water.brown algaein plants Frequent water changes can reduce the nitrate and phosphate content of the water. This is the best solution to get rid of brown algae.

Does brown algae mean my tank won't drive?

Not necessarily. Brown algae can appear during the cycle process, which is very common. But it can also happen in an established tank.Brown algae is not a common type of algae., but they are a tiny animal, diatoms.

Should I remove dead plants from the aquarium?

Yes, dead plant debris should be removed as soon as possible. The rotten parts of the plant decomposecausing the tank to smell badand they also form ammonia, which is fatal to fish.

Is it difficult to keep live plants in an aquarium?

In my opinion it is not. Keeping the plants in the aquarium is as easy as keeping the fish. Just a few other things need special attention to have plants in your aquarium. Light and substrate are the main consideration among them.

Do live plants need soil in an aquarium?

Soils that are particularly rich in minerals are ideal for growing plants in the aquarium. Although there are many types of plants that do well in any substrate. You can choose the simplest plants for this.can grow on graveljArenaAlso.

(Video) Why New Aquariums Go BROWN | Fixing Brown Diatom ALGAE

To load

The three critical factors in caring for your green are lighting, water conditions, and substrate. Make sure you keep these things in order and your planted tank will thrive. Consider the following points:

  • Choose the right plants and ensure enough lighting and a suitable substrate.
  • Perform water tests and water changes regularly.
  • Make sure effective filtration is installed and working properly.
  • If you keep the plants in a lot of light, use CO2supplement and use correctly.
  • Choose the right type of fertilizer when fertilizing. Liquid fertilizer makes sense.
  • Author
  • recent posts

Sujit Modak

Hey guys! I am Sujit Modak. I am the creator and editor of this fishing blog. Fishing is my passion and I started this fascinating hobby in 2006. My goal is to share my knowledge with you to support you on your fishing journey.

Latest posts by Sujit Modak(see it all)

  • Why are my aquarium plants turning brown? learn to overcome- March 5, 2023
  • Should I turn off my aquarium light at night? find fact- February 19, 2023
  • The 9 Best Plants to Attach to Driftwood - The first three are great- February 19, 2023


1. Why Aquarium Plants Melt, Die & How to Easily Prevent or Stop it! Prevent Submerged Plants Melting.
(The Secret History Living in Your Aquarium)
2. Aquarium Plants Dying Plant Deficiencies Plants 101
(Aquarium Co-Op)
3. why plant leaves turn brown and dry on the ends
(Organic Gardening)
4. Why Micranthemum 'Monte Carlo' Turns Brown
(JJ Aquariums)
5. 7 Tips To Stop Brown Tips On Your Spider Plant
(Sheffield Made Plants)
6. HOW TO STOP ALGAE! why I don't have any | MD FISH TANKS
(MD Fish Tanks)
Top Articles
Latest Posts
Article information

Author: Moshe Kshlerin

Last Updated: 05/06/2023

Views: 6038

Rating: 4.7 / 5 (77 voted)

Reviews: 92% of readers found this page helpful

Author information

Name: Moshe Kshlerin

Birthday: 1994-01-25

Address: Suite 609 315 Lupita Unions, Ronnieburgh, MI 62697

Phone: +2424755286529

Job: District Education Designer

Hobby: Yoga, Gunsmithing, Singing, 3D printing, Nordic skating, Soapmaking, Juggling

Introduction: My name is Moshe Kshlerin, I am a gleaming, attractive, outstanding, pleasant, delightful, outstanding, famous person who loves writing and wants to share my knowledge and understanding with you.