Skip to Content

Why Your Java Fern Is Not Growing And How To Get It To Grow!

Due to java fern being such a low maintenance plant that can offer a range of benefits to most planted aquarium setups, it has always been a very popular option within the aquarium keeping community.

More recently though, it has started to become popular with aquascapes and with there being a huge number of beginners to aquascaping right now, we have noticed a spike in the number of people reaching out and asking why their java fern is not growing.

The most common problems that can stop your java fern from growing include problems with your nutrient levels and problems with your aquariums light intensity and the lighting time frames.

In some cases, a lack of CO2 in your aquariums water can drastically slow the growth rate of java fern to a pace that can be easy for people to mistake as their plant not growing.

Thankfully, these are all very easy to fix and the vast majority of people should easily be able to correct these problems that are causing their java fern not to grow.

Once the underlying problem that is causing your java fern not to grow has been corrected, you can usually expect to see growth spikes in as little as a week but we usually recommend people wait at least ten days.

Is It Normal For My Java Fern Not To Grow?

It can be normal and natural for java fern to not grow when first submerged as it needs to adapt to aquatic life.

The emerged leaves will slowly wither and aquatic leaves will grow that are better suited for the plant in submerged conditions. All other cases of java fern not growing are usually an indication of problems that you will have to investigate and fix as soon as possible.

Java fern can grow submerged, emersed or completely out of water with the plant being versatile to thrive in all three conditions with minimal assistance from you.

The problem with the plant occurs when you switch it from one environment to another as the plant needs time to adjust to living in different conditions.

If you have just added your java moss to your aquarium then we would usually recommend that you wait for around a month for the plant to adjust to submerged or emerced living depending on your tank setup before you expect to see growth.

Even if you have just purchased your java fern from someone else who kept it fully submerged in their tanks, it can still take a few weeks for the java fern to settle in to your tank conditions and start growing.

Why Is My Java Fern Not Growing?

Java fern is a surprisingly robust plant that will usually not have any major problems with it growing in most conditions.

In the rare situation that java fern does not grow at a rapid pace, you will usually find that your aquarium has problems with the nutrient levels in the water of the light intensity or light durations with the plant being overwhelmed.

If you have an aquarium setup where you have to do full water changes on a regular basis then this can cause problems with your java fern in some situations as the plant thinks that its living conditions are changing so it stops growing to adjust to living out of water.

If you try to keep your full water changes to less than thirty minutes then this should prevent you from having any problems with your java fern not growing but even then, it really is rare that you will have any serious problems with java fern due to water changes in your tank.

There is a common misbelieve that problems with water flow in your aquarium can cause your java fern to stop growing but this is very unlikely.

In a very small number of setups where the water flow levels are very high there can be problems but for the vast majority of people who are keeping aquariums, their water flow rates should not be a problem and the java fern in your tank should be able to grow fine.

How Can I Get My Java Fern To Grow?

Checking your water parameters and water nutrient levels to make sure that your aquarium water has everything that your java fern requires to grow is the best way to get your java fern to grow.

Making sure that you offer your java fern a moderate light intensity for around six hours per day is also a quick and easy win to help your java fern grow too.

With many beginners to aquarium keeping using cheaper lighting units, lighting intensity can be a real problem for some tank setups.

This can be sure to the lighting intensity control dial on the lighting unit not being accurate of the actual light emitted from the lighting unit not being consistent resulting in your java fern not growing correctly.

In some cases, ammonia and nitrate levels in your aquarium can also cause problems and java fern tends to prefer “dirty water” with a slightly higher nitrate level than usual to grow.

Due to how robust java fern is, this really is rare though and is usually the last thing to check in your aquarium if you do notice your java fern having problems growing at a steady pace.

Does Java Fern Need CO2 In The Water To Grow?

Just like many other plants commonly used in the aquarium keeping hobby, java fern does not actually need additional CO2 added to its water supply to grow.

That said, increasing the CO2 in your aquariums water is a quick and easy way to get your java fern to grow at a faster pace but most beginners tend not to have the equipment required to increase their CO2 levels.

This is why we would always recommend that you just stick to the methods that we have covered above to investigate the conditions in your aquarium to try and find any other possible problems that you may be having in your aquarium.

For the majority of people, the issue will be due to lighting or nutrition in your aquarium and once they have been corrected, you should easily be able to get your java fern growing again.

If you are a more experienced aquascaper and you have invested in your hobby to have access to CO2 injection systems or other CO2 delivery methods that you are able to use with your aquarium then you may be able to look at increasing the CO2 levels in your tank.

Just remember to check that everything in your aquarium will be fine with the increased CO2 levels and that you will not accidently cause other problems.


That brings our article going over why your java fern is not growing to an end. We hope that we have been able to help you better identify the potential problems that may be causing your java fern to have problems growing and not grow at the required rate. Thankfully, java fern tends to recover quickly and then get back to its normal growth rate once the problems in its tank have been corrected so you shouldn’t have any long term problems to worry about.