Home » Fish Guides » Ammonia Burn On Goldfish | (Why Your Goldfish Is Turning Black?)

Ammonia Burn On Goldfish | (Why Your Goldfish Is Turning Black?)

Goldfish are known as pretty hardy fish. But, they are also prone to diseases like any other fish. Ammonia burns on Goldfish are one such disease that Goldfish get when living in poor water conditions.

Clean water conditions are one of the few things Goldfish require to thrive in an aquarium. When they lived in poor water conditions, they would also get ill.

Also known as “new tank syndrome,” Ammonia burns occur when fish get poisoned by Ammonia. If left untreated, it can cause death in your pet.

So, let’s dive deep into today’s topic, “Ammonia burn on goldfish.” 

Ammonia Burn On Goldfish

Ammonia burn on Goldfish

Like any other creature, Goldfish also produces Ammonia as a waste product.

They release Ammonia through their feces and through their gills. The leftover food and dead and decaying matters also release Ammonia as they decay.

When the tank has no way to break down Ammonia into nitrite and nitrate, and you don’t clean the tank well, Ammonia levels start to increase to a level that harms your Goldfish.

Ammonia burns the fish’s gills, causing them to stop breathing and eventually die. Consequently, unless you act fast, ammonia poisoning can be fatal.

Unfortunately, Ammonia has no color. So, there is no way to detect Ammonia poisoning when your tank’s Ammonia levels increase.

When you see any signs or symptoms of your fish, it might be too late.

What does ammonia burn look like on fish (signs of ammonia burns)

As we said before, seeing any signs or symptoms of Ammonia burns isn’t a good sign. When you notice any of these signs listed below, you need to act fast and treat your fish.

Common symptoms of Ammonia burns are,

  • Difficulty breathing
  • Lethargy
  • Loss of appetite
  • Wasting
  • Increased mucus production
  • Inflamed gills
  • Sitting at the bottom of the tank
  • Red burns on the skin
  • Blood splatters on the tail and fins

If your tank is a new one and has not cycled before, there is a high chance that your fish will show these symptoms. That is why it is commonly known as “new tank syndrome.”

What causes ammonia poisoning in fish (causes of ammonia burn)?

Although the leading cause of Ammonia poisoning is not cycling your new tank (hence the name), there are several other causes of Ammonia burn on Goldfish.

Overfeeding your fish

When you overfeed your Goldfish, they will produce more waste than usual. And also, the excess food will sink to the bottom and produce Ammonia as they decay.

This will cause an instant increase in Ammonia levels which your filters can not handle anymore. As your tank gets more and more Ammonia, your Goldfish suffers from Ammonia burns.

Overcrowded tank

When your tank has too many fish, they will produce more waste, hence more Ammonia.

When the filtration system is not powerful enough, the Ammonia levels will increase. This will cause your fish to get poisoned and suffer.

Insufficiant filtration

Even if you have a well-cycled tank with few fish, your tank can get high Ammonia levels when you have a poor water filter.

The filter needs to be powerful enough to filter all the water in your tank. Otherwise, your tank will have poor water conditions.

Insufficient filtration can cause increased Ammonia levels in the tank, and your Goldfish will suffer from Ammonia burns.

Adding untreated tap water

Tap water can contain Ammonia and other toxic chemicals to your Goldfish. If you add tap water without treating, this can cause Ammonia burns on your Goldfish.

Incorrect pH levels

When the pH level of your tank is too high or too low, it will cause the “good bacteria” to stop working.

When good bacteria like the bacterium Nitrosomonas stop working, the tank’s nitrogen cycle ceases.

Since the nitrogen cycle is the main reason a fish tank controls Ammonia levels, ceasing it will cause a sudden increase in Ammonia levels, which causes Ammonia poisoning in your Goldfish.

Is ammonia poisoning in fish contagious?

Ammonia poisoning is not contagious. One infected fish can not spread the disease to another fish.

However, since all fish are living in the same water conditions, other fish in the tank can also get caught with this disease (and they surely will if you do not step in).

So, if you observe a sick goldfish, it won’t be long before other fish in the tank become ill as well.

Can a goldfish recover from ammonia poisoning?

A goldfish can not recover from ammonia poisoning if kept in the same water conditions even after seeing the physical signs and symptoms.

If kept in the same water conditions, your fish will, unfortunately, die soon. However, if you remove

Ammonia as soon as you detect the problem, your fish will have a chance to recover if the damage is not too extensive.

Can fish survive ammonia burns?

Unfortunately, most fish will not survive Ammonia burns and die. Fish shows signs and symptoms of Ammonia poisoning, mostly after the toxins severely damage them.

So, when you observe changes in your fish, it might be too late, and your fish will die within a day or two. However, you can save other fish from suffering if they still look healthy.

How do you treat an ammonia burn on a goldfish?

Unfortunately, no medicine can treat Ammonia burns on Goldfish. The only treatment option is to reduce the Ammonia level of the tank.

Even after lowering the Ammonia levels, there is a high chance that your fish will die because their gills are already damaged to a severe level.

To reduce the Ammonia levels in your fish tank, you need to have a way to check the water parameters.

You can use test strips such as Tetra Easy Strips Ammonia Test Strips or buy a test kit to monitor Ammonia levels continuously.

We recommend Alert Series Ammonia Alert as it uses sensor technology to detect Ammonia levels. So, when the Ammonia level changes, the kit changes its color to signal how much Ammonia is in the water.

How do you fix ammonia poisoning in a fish tank?

You can fix Ammonia poisoning in your tank by following these steps.

Step 1: Find out the root problem

Reducing the Ammonia levels without fixing the root problem of Ammonia poisoning is useless because the underlying problem remains.

In a healthy aquarium, Beneficial bacteria turn down Ammonia into less toxic substances. But, when the Ammonia production is too much, the “good” bacteria and the filtration system can not process the nitrogen cycle well.

Overcrowding the aquarium and excessive feeding can all promote ammonia level spikes. Therefore, you should first fix the root cause of increased Ammonia levels to dive into other steps.

Step 2: Remove your sick fish to a quarantine tank

Since your fish is already suffering, removing the sick fish into a quarantine tank is better to ease the suffering.

But, be sure that the quarantine tank is also cycled and has filtration media to break down Ammonia.

Step 3: Drastically reduce or stop feeding

When you reduce or stop feeding, it will cause less fish waste and less rotten food. It means one less reason for increased ammonia levels.

Do not be afraid to reduce or stop feeding your Goldfish because Goldfish can live a long time without eating any food. You can keep Ammonia levels under control by following this step.

Step 4: Increase water changes in your tank

As your tank already has increased Ammonia levels, you should manually reduce the Ammonia levels in your tank.

To do this, you should perform water changes than before. As significant water changes at a time can stress out your fish, you can do 25% water changes every day until the water parameters stabilize.

When you observe zero Ammonia, zero nitrites, and some nitrate in your test kit, you know your tank is cycled.

Step 5: Add beneficial bacteria to the tank

Most often, an Ammonia spike happens in an established tank when the beneficial bacteria already present in the tank can not process them all.

This often happens when you add new fish to the tank or when you overfeed your fish. In that case, you can supplement beneficial bacteria by adding bottled bacteria such as API QuickStart.

Since your fish are already suffering from Ammonia Spike, our target is to lower the Ammonia level.

While following all other steps, adding beneficial bacteria to the tank also helps reduce the Ammonia level.

Step 6: Increase the Aeration of your tank

Ammonia burns can permanently damage your fish’s ability to breathe. Therefore, even after your fish survives an Ammonia poisoning, it will suffer its whole life because of difficulty in breathing.

So, it is essential to help your fish breathe easily by increasing the aeration of your tank.

You can add air stones and bubblers along with a more powerful filter system to increase the oxygenation of your tank.

As cold water can hold more oxygens, you can also try lowering the water temperature. As Goldfish are cold-water fish, they will appreciate your effort.

How to prevent ammonia burns on Goldfish?

Ammonia burns on Goldfish are almost impossible to cure.

When fish get affected by Ammonia poisoning, it won’t take long for your poor thing to die. Therefore, it is vital to prevent Ammonia burns on Goldfish.

Fortunately, it is easier to prevent Ammonia spikes in a fish tank than reduce Ammonia levels. Below are the steps you should follow to avoid ammonia burns on your Goldfish.

Properly cycle new fish tanks

As new tanks can not process the Nitrogen cycle properly, you have to let it establish for about two weeks until the environment itself build up beneficial bacteria.

However, you can speed up this process by introducing beneficial bacteria from outside. Some sources are,

  • Filter media from an already established tank
  • Aquarium plants
  • Garden soil
  • Compost and
  • Bottled bacteria.

Once the tank is cycled, you can slowly add a few fish at a time to establish your tank.

Do not add too many fish to your tank

Although having an aquarium full of fish is pleasant to watch, it is not pleasing to your fish. An overcrowded tank can increase the stress on your fish and can increase ammonia levels.

So, avoid adding too many fish to your tank at all costs. If possible, buy a larger tank and transfer your fish to that so that you can keep all your fish.

Do not overfeed your fish

When you feed your fish only the amount they need within 3 minutes and keep your feedings to about two times per day, you can easily control overfeeding problem.

As Goldfish are intelligent animals, they will ask for food every time you go near the tank. But, do not be fooled by this behavior, as you are already feeding them enough.


Ammonia burn on Goldfish is often fatal to fish. Hence it is crucial to take measures to prevent Ammonia spikes in your aquarium.

If your fish get affected by Ammonia poisoning, you should immediately take action to reduce excess Ammonia from the tank.

The ideal Ammonia level in a fish tank is 0ppm. However, fish can tolerate Ammonia up to 0.06ppm. If you want your fish to thrive in your aquarium, you must avoid Ammonia in your tank.

Credit to : Exotic Aqua Life
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About Dr.Chamika

Hello, I'm Dr. Chamika. I am a Researcher in Water quality, Aquatic organisms, and Environmental chemistry. I am a passionate fish keeper, with10 years of experience. My mission is to help other aquarists experience the joy of fish keeping.