6 Reasons Your Amazon Frogbit Is Dying And How To Fix It!

Your Amazon frogbit may be dying due to factors such as insufficient lighting, inadequate nutrients, poor water quality, extreme temperatures, overplanting, infections, or a lack of CO2. Understanding and addressing these issues can help ensure the plant’s health in your aquarium.

Amazon frogbit is a popular floating plant in the aquarium hobby. I use it in my larger tanks because it offers shelter for my fish and helps regulate the nitrogen cycle.

Although Amazon frogbit is considered beginner-friendly, people often encounter problems that cause their frogbit to die.

When the frogbit in my community tank recently started dying, I researched the topic and wanted to share my findings, as this seems to be a common problem.

Common Signs Your Amazon Frogbit Is Dying!

Amazon Frogbit Turning Brown
Amazon Frogbit Turning Brown

The most common signs of a dying Amazon frogbit plant range from changes in leaf color to actual holes forming in the plant’s leaves.

The table below goes over the more common signs that your frogbit is dying and offers solutions for each issue to try and help you nurse your plant back to full health.

Yellowing LeavesEnsure adequate nutrient levels. Consider adding a balanced liquid fertilizer. Check lighting conditions, as excessive light can also cause yellowing.
Browning LeavesAdjust light levels and ensure it’s not exposed to intense direct sunlight. Ensure water parameters (pH, ammonia, etc.) are in the appropriate range.
Melting LeavesCheck water quality and parameters. Ensure the absence of harmful chemicals. Adjust lighting if it’s too intense.
Holes in LeavesEnsure adequate nutrient levels. Inspect for pests such as snails or insects. Some fish may also nibble on Frogbit.
Reduced BuoyancyInspect roots for health. Ensure water parameters are stable. Adjust nutrient levels if required.
Decaying RootsEnsure good water quality. Avoid excessive water agitation. Consider trimming away decaying sections to prevent further rot.

Some of these problems are not as straightforward as people think and people often have multiple problems causing their frogbit to die.

Why Is My Frogbit Dying?

Amazon Frogbit
Amazon Frogbit

Here are the most common reasons that Amazon frogbit starts dying:

  1. Insufficient Light
  2. Inadequate Nutrients
  3. Poor Water Quality
  4. Extreme Temperatures
  5. Over Planting
  6. Infection
  7. A Lack Of CO2

In my experience, people usually have problems with lighting, nutrients, and water quality so I would recommend that you start checking for problems with them before looking at temperature, stocking, and CO2.

Insufficient Light

The LIghting Unit On My Tank
The Lighting Unit On My Tank

Insufficient lighting is a common reason Amazon frogbit starts dying, typically indicated by the leaves losing their color before the plant begins to die.

This often happens because the stock lights that come with aquarium kits are too weak to provide the necessary light for the frogbit to thrive.

I encountered this exact issue with the frogbit in my community tank, as the default light that came with the tank was too weak to support healthy plant growth.

Fortunately, the health of my Amazon frogbit improved within days of upgrading to a budget-friendly aquarium light, and the plant has thrived ever since.

If you are using a stock aquarium light and notice the leaves of your frogbit turning yellow or brown or starting to melt, it may be due to insufficient lighting. Upgrading to a suitable inexpensive light or any other lighting unit designed to promote healthy plant growth should resolve the issue quickly and help your frogbit thrive.

Inadequate Nutrients

My Plant Fertilizer
My Plant Fertilizer

A lack of essential nutrients is a common cause of Amazon frogbit dying, with yellowing leaves and holes forming in the plant being typical symptoms.

Beginners often mistakenly believe that fish waste alone is sufficient to nourish the plants in their tank. While fish waste in heavily stocked tanks can provide some macronutrients, it usually isn’t enough to maintain healthy plants.

Most aquarium plant fertilizers on the market contain essential macronutrients needed for healthy plant growth. However, fish waste often lacks the essential micronutrients necessary for aquatic plants, and many popular aquarium fertilizers are also deficient in these minerals.

I previously used Tropical Premium Nutrition as my plant fertilizer, but it lacks nitrogen and phosphorus, assuming that fish waste will meet these needs. This wasn’t sufficient for my tank, so I switched to Tropica Specialised Nutrition, which includes nitrogen and phosphorus, making it nutritionally complete. Since then, all of my plants have thrived.

The dropper system on the Tropica bottle makes it easy to dose the formula correctly, allowing me to quickly replenish the nutrients in my tank and support plant health.

If you notice yellow, holey leaves on your Amazon frogbit and are not using a plant fertilizer, a lack of nutrition may be the cause. I prefer Tropica fertilizers, but any good plant fertilizer should help increase the nutrient levels in your tank and support your frogbit’s growth.

Poor Water Quality

My Tanks Water Parameters
My Tanks Water Parameters

Poor water quality can cause several issues with Amazon frogbit, eventually leading to the plant’s decline.

This can be tricky to diagnose because Amazon frogbit can thrive in tanks with slightly elevated ammonia, nitrite, and nitrate levels. However, ammonia and nitrite levels above 1 ppm and nitrate levels above 50 ppm can start to cause problems for your frogbit.

Use a reliable water test kit to check the toxin levels in your tank. If you don’t have access to a test kit, monitor your fish for signs of stress such as rapid breathing, lethargy, and red gills, as fish are more sensitive to these toxins than plants.

A partial water change of 20-50% can help temporarily reduce ammonia, nitrite, and nitrate levels. However, the problem will persist if your tank lacks beneficial bacteria colonies to manage these toxins.

I highly recommend performing a partial water change if you have high toxin levels. Levels high enough to harm your frogbit will definitely cause problems for your fish.

Extreme Temperatures

My Tank Heater
My Tank Heater

Extreme temperatures can cause several problems for Amazon frogbit, potentially leading to the plant’s death.

There are many contradictory sources regarding the recommended temperature ranges for Amazon frogbit. I typically follow the Dennerle recommendation, as they propagate plants on an industrial scale and sell them worldwide. Their recommended temperature range for Amazon frogbit is 65-82°F (18-28°C).

Keeping your Amazon frogbit outside of these temperature ranges can result in browning leaves, melting leaves, buoyancy issues, and decaying roots, eventually leading to the plant’s death.

Even within these ranges, a weak strain of Amazon frogbit might still experience problems at the extremes.

A cheap aquarium thermometer can easily monitor the water temperature in your tank. If you identify any issues, you can adjust your tank heater as needed.


My Community Tank
My Community Tank

Although rare, overplanting can deplete the nutritional levels in your aquarium as all the plants compete for the same nutrients.

In the photograph above, you can see my community tank, which I would describe as lightly to moderately planted.

Given this, I’m confident that overplanting is not the reason my Amazon frogbit started to die. However, in a heavily planted tank without regular fertilizer dosing, this can indeed be an issue.

If you have a heavily planted tank and notice your Amazon frogbit developing yellow or brown leaves, melting leaves, buoyancy issues, or decaying roots, overplanting may be the problem.

Dosing your aquarium with a good fertilizer should help correct any nutrient deficiencies caused by overplanting. Additionally, you may need to add extra lighting to support a large number of surface plants.


Fortunately, I have never experienced issues with my Amazon frogbit being infected by parasites or fungus, but this can be a significant problem for some people.

Typically, you can identify the infection through visual symptoms such as white cottony growths or visible parasites on the plant.

In most cases, a general anti-parasitic or anti-fungal treatment can address the infection, allowing the Amazon frogbit to fully recover within a few weeks.

If possible, quarantine the affected frogbit for treatment to prevent the medication from causing problems for your fish and other plants.

My Amazon Frogbit Jar
My Amazon Frogbit Jar

Even a basic jar will be enough for treatment and my spare Amazon frogbit thrives in my frogbit jar.

A Lack Of CO2

Amazon Frogbit In My Tank
Amazon Frogbit In My Tank

CO2 is optional for frogbit, but it can promote healthy growth in heavily planted tanks.

One common drawback of using CO2 with Amazon frogbit is the significantly increased growth rate, which requires trimming the roots every two to three days.

If your Amazon frogbit is in a heavily planted tank and shows signs of stunted growth, yellow or brown leaves, or melting leaves, adding CO2 might help.

However, I would first consider addressing the other potential issues mentioned earlier in the article, as CO2 kits can be expensive.

Final Thoughts

Balancing elements like lighting, nutrient levels, and water quality is essential for the well-being of your Amazon frogbit.

Frogbit is a beginner-friendly plant that offers plenty of advantages to an aquarium but its challenges can be problematic for novices who are still getting used to managing the nitrogen cycle in their tank.

Use the table earlier in the article to correctly identify the problem with your frogbit and start to correct the problem in your tank as quickly as possible and your frogbit will be thriving in no time.