5 Reasons For Java Fern Turning Brown -Troubleshooting

Java ferns are one of the most beautiful and attractive additions to any tank because they are so easy to take care of and tough and hard in nature. In addition, they require a very little amount of fertilizers and light which makes them an exceptional choice for aquarists.

However, sometimes this blessing can also be a problem. Since they have such low requirements they can easily be disturbed and start turning their leaves brown and become unattractive if their needs are overly filled. 

Now, Here are 5 reasons that cause Java Fern to turn brown

  • Struggling with adaptation
  • Too much sunlight
  • Wrong placement
  • Nutrient deficiency
  • Algae overgrowth

And the sad news is these reasons will also cause the java fern to turn black and melt away as well.

However, The cool thing is in this article I am going to talk about all these problems and discuss how you can solve the browning of java fern totally like an expert.

So, without making any delay let’s get this show on the road–

Why is the Java Fern Turning Brown-Solution

java fern brown leaves

1. Struggling with Adaptation

When the java ferns are put into a tank they will take some time to make adjustments to the new environment. And while they try to adapt to the new growing condition, their leaves can turn brown around the margin. 

Also, many of the java ferns are grown as partially submerged plants. In that case, they will need time to get adjusted to the fully aquatic condition of the aquarium.

Control Measure

Once you notice the java fern leaves are turning brown then you have to take some immediate steps. First off, remove the oddly-looking brown leaves so that they can have enough space to grow more leaves from the underside.

In addition, add some small amounts of fertilizers so that they can have enough nutrients to help them establish themselves in the new area.

2. Too Much Sunlight

The thing is, the java moss is found on the lower levels of the rainforest where sunlight cannot reach properly and they are accustomed to this damp and shaded condition.

So, if your tank has too many hours of light then the ferns can turn their leaves brown as an indication of their discomfort.

If you notice a java fern that was already established but suddenly starting to turn its leaves brown, it’s time for you to think about the light setup.

Control Measure

One thing you can do is reduce the intensity of the lights in the aquarium. Or another way is, you can place them in a way that other plants or aquarium decorations provide the ferns some shade from the light.

Since some of your other plants might need a good light intensity you have to Increase the intensity of the lights very slowly so that the ferns can gradually adapt to the condition.

3. Wrong Placement

If your ferns have started to turn brown just after you’ve planted then you might need to recheck the planting situation. Because these are aquatic plants and they do not have true roots.

Instead, they have some hair-like structures called rhizomes. And the java ferns use these to anchor themselves to some rough surfaces like driftwood.

So, if you have planted them in a tank substrate they are most likely to stop growing and turn brown very soon. Eventually, the plant will die.

Control Measure

You have to plant them on the right surface that they can use to anchor. In the beginning, you can use some wires or any kind of rubber bands to help them attach their rhizomes to a rock or driftwood.

Naturally, they will hold the surface on their own for some time and you can then remove the additional wire attachments from them.

4. Nutrient Deficiency

Since they are not grown in substrates like other plants, the substrate fertilizers will not work on them. Actually, they uptake nutrients directly from the water with the help of their leaves and rhizomes.

So if you are using normal kinds of fertilizers then they will fall victim to nutritional deficiencies and turn their leaves brown.

Sometimes in severe nutritional deficiency, the leaves will turn black, especially from the tips. In addition, the Java ferns will be too weak to fight any fungal or bacterial diseases.

Control Measure

To make this right, you have to use liquid aquarium fertilizers in small amounts whenever you change the water. This will also encourage them to make better anchorage and grow more leaves. (Our Pick: Aqueon Plant Food)

But be careful about the amount because an overdose of nutrients will easily burn the leaves of the java fern. Because if the phosphate levels in your tank become too high then the java leaves will have transparent or clear tips on the leaves. And this will ruin the beauty of your tank.

You can also use additional CO2 in the tank to help them grow. However, they are very slow-growing ones so don’t expect them to grow much even after giving them the fertilizers.

Here is a combo that you can check for your Java Fern- Seachem Flourish Freshwater Plant Supplement & API Co2 Booster Freshwater Aquarium Plant Treatment.

5. Too Much Algae Growth

This is a very concerning issue if your tank has an excessive growth of algae. Because these things are very invasive, especially cyanobacteria which are known as blue-green algae. They attack the java ferns and take up most of their necessary liquid nutrients.

Control Measure

To deal with the algae you have to reduce the light in your tank. Because they love to grow in the presence of too much light.

Also, you have to change the water in your tank very frequently. Every two or three days change and refill at least 10-20 % of water followed by the addition of a small amount of liquid fertilizers.

Moreover, you can manually remove the algae by cleaning your tank glass with an algae scraper on a regular basis. This step might not remove all of the algae population but it will definitely keep your java ferns from browning.

How to Trim Java Fern

java fern plants trimming

You can trim the java ferns to remove the dead leaves and to keep them under a preferable size according to your tank. Also if you want to propagate them then trimming is the best option.

If you cut the rhizome in half, it will generate a new plant from each piece. This is how easily the Java ferns can be propagated even by a beginner. However, remember to let both pieces have some leaves while you cut. 

And if you trim the plant, it will produce new shoots from the cut points. And the shoots will further grow leaves. But this is a very slow process.

Also, you can trim the leaves and roots of your plant to make space in the tank. In any sort of pruning, you have to use very sharp scissors for Java ferns. Because if you do it with a knife the cuts will not be very smooth and efficient for further growth.

Another thing is, trimming inside the aquarium can be very problematic because of the flow of water and it can even cause damage to other plants and fishes. So it is best if you do it during water change when the water level is lower than usual.

Frequently Asked Questions (FAQs)

What Fish Pairs Well With The Java Fern?

Java ferns are very tough and hardy plants so any kind of freshwater fish can be easily kept with them in the tank. However, if the fish size is too large then it can cause some damage to the leaves but otherwise, they are good to go with any tank fish.

Can The Java Fern Be Grown Entirely Out Of Water?

The thing is, java ferns are aquatic or semi-aquatic kinds of plants so they need a lot of humid conditions and a wet environment for their survival and growth. Moreover, they don’t have true roots. So they are not suitable for growing in a pot.

Should I Cut Off The Brown Java Fern Leaves?

Once the java fern leaves have turned brown they will not turn back to green so to make the tank look more attractive you can surely get rid of the brown and dead leaves with sharp scissors. And it will also keep your tank healthy.

How Much Light Does A Java Fern Need?

The Java ferns require a  very small amount of light. They will happily grow under dim light conditions below 3 watts per hour at least for 6 hours. However, they should never be exposed to any light more than 12 hours a day.


Follow all the simple control measures and give yourself a pat in the back. Because this is all the Java ferns ask of you. Be careful about the lights and fertilizer issues and you are all set. 

Though sometimes they may have brown spots on them because of old age which is a kind of unsolvable issue. 

Now that you have all the information about the reasons for Java Fern turning brown, you can easily battle any of these causes and get your ferns back to their healthy and leafy form. If you have any more questions about these beauties feel free to ask in the comment section below.

Howard Parker

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