Skip to Content

10 Reasons Your Java Moss Is Not Growing In Your Tank!

Java moss is one of the most common aquatic plants kept within the fish keeping community due to it being so cheap, readily available, and easy to keep.

That said, although java moss is a very beginner friendly aquatic plant, we do commonly see people reaching out each month with a number of potential problems.

If you are new to keeping plants in your tank then these problems can be easy to make so for todays article, we want to be taking a look at why your java moss is not growing to try and help as many of our readers as possible.

Please note, if you are a beginner then there is a high chance that you may have multiple issues with your tank covered in our article below rather than just one so be sure to consider all causes of a slow growth rate for your java moss.

Why Is My Java Moss Not Growing?

We have a list of the most common reasons that your java moss may not be growing below and then we will take a more in-depth look at each of the causes:-

  • Low Quality Water!
  • A Lack Of Nutrients In The Tank!
  • Unsuitable Water Flow!
  • Sudden Change In Water Flow Parameters!
  • The Placement Of The Java Moss!
  • Unsuitable Light!
  • Tank Mates Eating It
  • Water pH Levels!
  • Ammonia And Nitrate Levels!
  • Water Temperature!

Please note, if you have recently just submerged your java moss then it can be totally normal for it to have a slow growth rate for a couple of weeks. We go into this in more detail in our article on growing java moss emersed if you want to check it out.

Low Quality Water!

One of the first things to consider when trying to work out why your java moss is not growing as it should be is the quality of the water that you have in your tank.

As we have said before, although java moss is a very beginner friendly aquatic plant, it does still require a certain level of care and attention in order for it to thrive.

This means that if you are keeping your java moss in a tank with water that has a high level of ammonia or nitrates then this could be the reason why it is not growing.

We would always recommend testing your water quality on a regular basis to ensure that there are no issues that could be harming your aquatic plants.

If you use tap water for your water changes without using a conditioner to remove the chlorine in the tap water then this can also slow the growth rate of your java moss too.

A Lack Of Nutrients In The Tank!

Another common reason that your java moss may not be growing is due to a lack of nutrients in the tank.

Although java moss is not a particularly demanding plant when it comes to nutrients, it does still need a certain level of them in order to grow at its best.

If you are not using a fertilizer in your tank or if you are not feeding your fish live or frozen foods then this could be the reason why your java moss is struggling.

It is also worth noting that if you have a lot of algae in your tank then this can compete with your java moss for nutrients which can again lead to slower growth rates.

Unsuitable Water Flow!

One of the most common reasons that people have problems with their java moss is due to unsuitable water flow.

Java moss is a plant that originates from slow moving waters so it does not require a lot of water flow in order for it to grow.

In fact, if you have too much water flow in your tank then this can actually damage the delicate leaves of your java moss which will lead to slower growth rates.

Sudden Change In Water Flow Parameters!

Another common issue that we see with java moss is a sudden change in water flow parameters.

If you have recently changed the water flow in your tank then this could be the reason why your java moss is not growing.

Java moss is a very delicate plant so even a small change in water flow can have an adverse effect on its growth.

The Placement Of The Java Moss!

Another thing to consider when trying to work out why your java moss is not growing is the placement of the java moss in your tank.

If you have placed your java moss in an area of your tank where there is not a lot of light then this could be the reason why it is not growing.

Java moss needs a minimum of 2-3 hours of direct sunlight per day in order to grow at its best.

If you are not providing enough light then this will lead to slower growth rates.

Unsuitable Light!

As we have just mentioned, one of the most common reasons that java moss does not grow well is due to unsuitable light.

Java moss needs a minimum of 2-3 hours of direct sunlight per day in order for it to grow at its best.

If you are not providing enough light then this will lead to slower growth rates.

It is also worth noting that if you are using artificial light then you need to make sure that the light is not too strong as this can also damage your java moss.

Tank Mates Eating It!

One of the more common reasons that java moss does not grow well is due to tank mates eating it.

If you have fish or other aquatic animals in your tank then they may be eating your java moss which will obviously lead to slower growth rates.

It is important to note that java moss is not toxic to most fish so if your fish are eating it then it could be an indication that you are not providing enough food in your tank.

The best way to stop your fish from eating your java moss is to provide them with plenty of hiding places and caves in your tank.

This will help to reduce the amount of stress that your fish are feeling which will in turn stop them from grazing on your java moss.

Water pH Levels!

One of the most important things to consider when trying to work out why your java moss is not growing well is the pH levels of your water.

Java moss prefers a neutral to slightly acidic pH level in order to grow at its best.

If your water has a high pH level then this can damage your java moss and lead to slower growth rates.

You can test the pH levels of your water using a simple test kit which you can purchase from your local pet store.

If you find that the pH levels of your water are too high then you can lower them by adding some driftwood or other aquarium plants to your tank.

Ammonia And Nitrate Levels!

Another thing to consider when trying to work out why your java moss is not growing well is the ammonia and nitrate levels in your water.

If these levels are too high then this can damage your java moss and lead to slower growth rates.

You can test the ammonia and nitrate levels of your water using a simple test kit which you can purchase from your local pet store.

If you find that the levels of ammonia or nitrate in your water are too high then you will need to take steps to lower them.

The best way to lower the levels of ammonia and nitrate in your water is to do a partial water change.

You should also make sure that you are feeding your fish the correct amount of food as overfeeding can lead to high levels of ammonia and nitrate in your water.

Water Temperature!

Another thing to consider when trying to work out why your java moss is not growing well is the temperature of your water.

Java moss prefers a water temperature of around 20-25 degrees Celsius in order to grow at its best.

If the temperature of your water is too high or too low then this can damage your java moss and lead to slower growth rates.

You can test the temperature of your water using a simple thermometer which you can purchase from your local pet store.

If you find that the temperature of your water is too high or too low then you will need to take steps to adjust it.

The best way to adjust the temperature of your water is to use a water heater or a chiller.

You should also make sure that you are using an aquarium hood in order to keep the temperature of your water stable.