Ammonia can be a problem for most aquarium fishes. It can lead to several illnesses in your goldfish too.
It would be best to check the ammonia levels in the tank to provide healthy life, as ammonia poisoning can be a disaster for your fish. So, what are the causes of ammonia poisoning in your goldfish? How can you treat ammonia poisoning in your goldfish? Let us find out.
Ammonia poisoning is when the high ammonia levels in the tank affect your goldfish. Improper cleaning, overstocking, and overfeeding can lead to ammonia poisoning in your fish. You can treat ammonia poisoning by doing a 50% water change and restricting food until the tank’s ammonia gets balanced.
The below article will discuss the causes behind ammonia poisoning in the tank. In addition, we will also learn how to treat ammonia poisoning in goldfish.

Contents
- 1 What is ammonia poisoning?
- 2 Is ammonia poisoning lethal for goldfish?
- 3 What are the symptoms of ammonia poisoning in goldfish?
- 4 What causes ammonia buildup in the goldfish tank?
- 5 How do you treat ammonia poisoning in goldfish?
- 6 How to treat ammonia burns in your goldfish?
- 7 Ways to prevent ammonia poisoning
- 8 Conclusion:
What is ammonia poisoning?
Ammonia(NH3)is an organic compound gas composed of hydrogen and nitrogen atoms. Ammonia poisoning is a negative effect of ammonia not being converted into the nitrogen cycle.
The nitrogen cycle is essential for a healthy tank as it helps the beneficial bacteria grow in the tank required to eliminate the harmful ammonia and nitrites.
So, when the ammonia is not being redistributed, it stops your goldfish from getting rid of the ammonia they produce, further leading to ammonia poisoning in your fish.
A small amount of ammonia in the tank is not life-threatening for your goldfish, but larger quantities can be lethal.
There can be numerous reasons for ammonia poisoning. Some of them are:
- Setting up a new tank
- Inadequate pH levels
- By-products of your fish
- Overcrowded tank.
- Not isolate your fish before adding them to your home aquarium.
- Chemically treated tap water
Is ammonia poisoning lethal for goldfish?
Ammonia in small amounts (Below 0.25ppm) is not a significant issue, but if it is present in larger quantities, it can lead to major health issues for your goldfish.
Excessive ammonia in the tank can affect the gills of your goldfish, making your fish sick and prone to several diseases and parasites.
Therefore it will be advisable to run water tests frequently to keep eyeing the ammonia levels in the tank.
Early detection of ammonia can prevent your goldfish suffer from severe health issues.
You should also perform a 30% water change weekly to maintain the tank’s water quality and prevent such issues for your goldfish.

What are the symptoms of ammonia poisoning in goldfish?
Here are the symptoms of ammonia poisoning in goldfish
- Your goldfish is gasping for air.
- Your goldfish is turning lethargic.
- Red or purple gills of your goldfish
- Your fish is laying at the bottom of the tank
- Your goldfish clamping their fins to their bodies
- Bloody patches on the body of your goldfish
Gasping for air
The initial symptom of ammonia poisoning in goldfish is your fish gasping for air at the water surface.
Ammonia in the tank indicates less dissolved oxygen in the water, making your goldfish suffer from a lack of oxygen and gasp for the air at the top of the tank’s water surface.
Also read: Can Goldfish Live Without Oxygen?
Lethargic
Your goldfish turning lethargic is also a symptom of ammonia poisoning in your goldfish.
Your goldfish will start losing appetite and be lethargic due to ammonia poisoning.
Also read: Why Is My Goldfish Lethargic?
Red or purple gills
Your goldfish’s red or purple gills indicate that your fish suffers from ammonia poisoning.
If not detected early, your fish tissues will start to deteriorate, and you will discover red streaks or bloody patches on their body and fins caused due to ammonia burns.
Laying at the tank’s bottom
Your goldfish laying at the tank’s bottom also indicates ammonia poisoning.
As ammonia spikes affect the gills of your goldfish, you will see your goldfish clamping their fins to their bodies and laying at the bottom of the tank.

What causes ammonia buildup in the goldfish tank?
Goldfish are messy fish that produce a lot of waste in the tank, leading to ammonia buildup in your aquarium.
If not cleared for an extended period, the waste in the tank will lead to ammonia buildup in the tank.
Overstocking your goldfish tank is also a significant reason behind ammonia buildup in the aquarium.
As goldfish excrete ammonia, adding more fish to the tank will increase the chances of ammonia in the tank.
Let us learn all the reasons in detail for ammonia buildup in your goldfish tank.
- Overfeeding
- Not isolating the new fish before adding them to the home aquarium,
- Leftovers
- Chemically treated tap water
- Overstocking
- Lack of cleaning
Overfeeding
Goldfish do not have a stomach to digest their food, so their intestine plays a vital role in digesting it.
So, when you overfeed your goldfish, it produces a lot of waste in the tank, eventually leading to ammonia buildup.
Overfeeding will also lead to leftovers in the tank. If not cleared, the uneaten food will rot, leading to ammonia buildup in the tank.
Not isolating the new fish.
There are chances that the fish you bought have been exposed to ammonia poisoning in their last tank.
In such a case, adding them directly to your home aquarium without isolating them can increase the chances of ammonia buildup in the tank.
In addition, it can also affect the other species in your home aquarium.
Chemically treated tap water
Adding tap water treated with a chemical to your tank can result in disaster for your goldfish leading to ammonia buildup in your goldfish aquarium.
Many water treatment companies use chloramine(chlorine bonded to ammonia) as an ideal disinfectant for city water systems.
Using tap water treated with such chemicals can lead to ammonia buildup in the tank, affecting the gills and causing several health issues for your goldfish.

Overstocking
Overstocking your goldfish tank can also lead to ammonia buildup in the tank.
As goldfish excrete ammonia, adding more fish to the tank will increase the chances of ammonia buildup.
For example, place one small goldfish in a 10-gallon tank until it reaches 2.5 inches.
However, adding more and more goldfish in the same amount of water will make you struggle with an ammonia buildup in the tank as your fish offload a lot of waste.
Overstocking can also affect growth and lead to excessive stress in your fish.
Lack of cleaning
Improper cleaning can also lead to ammonia buildup in the tank.
Leftovers, fish waste, and decayed plants, if not cleared from the tank, can rot and lead to ammonia spikes in the tank leading to severe health issues for your fish.
How do you treat ammonia poisoning in goldfish?
Here are the ways to treat ammonia poisoning in goldfish
- You can lower the water pH level to provide immediate relief to your goldfish. You can also perform a 50% water change to drop the ammonia level below one ppm. Performing frequent water changes will help to eliminate ammonia in the goldfish tank. The freshwater added should be of the same temperature as the aquarium, as a sudden change in the water temperature can stress your goldfish more, worsening the situation for your goldfish.
- You can use a PH control product to neutralize the ammonia in the tank if you discover your fish distressed.
- Stop feeding your goldfish for several days in case of high ammonia levels.
- Avoid adding new fish to the tank until the ammonia levels drop below 0.25ppm
- Goldfish with ammonia burns should be isolated in a separate tank and treated with antibacterial or antibiotic medication.
The above were the ways to treat ammonia poisoning in your goldfish.
It would be best not to ignore ammonia spikes in the tank, as ammonia in large volumes can lead to significant health issues for your goldfish.
How to treat ammonia burns in your goldfish?
Here are the ways to treat ammonia burns in your goldfish
- Firstly, by performing a water change, you should reduce the ammonia levels in the tank to below 0.25 ppm.
- Isolate the affected fish in a separate tank for the medication.
- Provide treatment to your fish with quality antibacterial and antibiotic medication.
- Avoid treating your goldfish in the home aquarium with antibiotics. It can weaken and even wholly kill off the biological filter bacteria, making you cycle your aquarium again.
- You will probably see the treatment results within 3-5 days. The treatment should continue till your goldfish is eating normally. Once your goldfish gets cured, you can shift them to the home aquarium.
Ways to prevent ammonia poisoning
Here are the ways to prevent ammonia poisoning in goldfish.
- Avoid Overfeeding your fish.
- Avoid overstocking your goldfish tank.
- Add filter
- Perform a regular water change
- Perform regular water tests in your tank.
- Isolating the new fish

Avoid Overfeeding
You should avoid overfeeding your goldfish to prevent such issues in your fish.
Goldfish are ravenous eaters that will eat anything you provide them.
However, as your fish do not have a stomach to digest their food, overfeeding will lead to much fish waste in the tank, leading to ammonia spikes and making your goldfish suffer from ammonia poisoning.
Overfeeding also leads to leftovers in the tank. If not removed from the tank, the uneaten food will rot, leading to ammonia buildup in your goldfish tank.
So, it will be advisable to provide the amount your goldfish can consume in under 2 minutes to avoid overfeeding and for the well-being of your fish.
Also read: Can Goldfish Die From Overfeeding?
Avoid Overstocking
You should avoid overstocking your goldfish tank to prevent ammonia poisoning in goldfish.
Goldfish are messy fishes that produce a lot of waste in the aquarium. Overstocking your goldfish will lead to more waste in the tank, making your goldfish suffer from ammonia poisoning.
Overstocking also comes with many other disadvantages for your goldfish. Some of them are as follows:
- Overstocking can lead to excessive stress in your goldfish.
- Overstocking can affect the growth of your fish.
- Overstocking can make your fish aggressive while competing for food.
- Overstocking can contaminate your goldfish tank water, making your fish gasp for air at the top of the tank’s water surface.
Therefore, you should avoid overstocking and provide ample space in your tank for the proper growth of your goldfish.
| Types of Goldfish | Minimum Size | Maximum Size | In a 10-Gallon Tank |
|---|---|---|---|
| Common Goldfish | 4 inches (10.16cm) | 14 inches (35.56cm) | 1-2 small Goldfish |
| Shubunkin Goldfish | 9 inches (22.86cm) | 18 inches(45.72cm) | 1 small goldfish |
| Comet Goldfish | 2 inches(5.08cm) | 12 inches(30.48cm) | 1-2 small goldfish |
| Fantail Goldfish | 6 inches(15.24cm) | 8 inches(20.32cm) | 1-2 small goldfish |
| Sarasa Goldfish | 4 inches( 10.16cm) | 14 inches(35.56cm) | 1-2 small goldfish |
