Ammonia Poisoning In Fish (Causes & Treatment)

Last Updated on 2023-08-08

There’s nothing worse than when you suspect your fish are suffering from ammonia poisoning. Not only is ammonia poisoning incredibly dangerous and fatal to fish, but it can also kill them incredibly quickly. In this article, not only are you going to find out what causes ammonia poisoning in fish, but you’ll also learn how to treat it as well!

So keep reading to find out everything there is to know!

What Is Ammonia Poisoning In Fish?

Toxic levels of ammonia are a leading cause of fish kills. It’s toxic to both saltwater and freshwater fish, but it’s especially harmful to freshwater fish that are more sensitive to changes in pH or water hardness. Ammonia poisoning, often known as “new tank syndrome,” is the result of having too much ammonia in a fish tank. Although naturally occurring in water, high concentrations of this chemical can cause serious health problems.

Although ammonia is not visible to the human eye, its presence will cause pH levels to appear lower than they actually are. That could make you think your tank is fine when, in fact, the water pH level is just getting higher. If you have a fish tank, you need to know what causes ammonia poisoning, how to treat your fish if they get sick, and what the symptoms are.

What Causes Ammonia Poisoning In Fish

There are a variety of causes of ammonia poisoning in fish, from overfeeding to improper pH levels. The following are examples of some of these.

The Tank’s Nitrogen Cycle Has Not Yet Been Established

Fish tank nitrogen problems might arise if the nitrogen cycle has not been established. Many sources, including decaying plant matter and the waste products of fish digestion, contribute to elevated ammonia levels in aquariums, highlighting the need for regular water changes. In order to prevent nitrogen poisoning in fish, the nitrogen cycle is essential for keeping ammonia levels constant throughout the tank.

As part of the nitrogen cycle, beneficial bacteria break down ammonia into less dangerous compounds like nitrites and nitrates.

Overfeeding the Fish

Both the fish and their tank surroundings might suffer from excessive feeding. Overfeeding fish can cause them to become poisoned by ammonia, but how precisely does this happen? Ammonia is produced during the decay of fish food. For this reason, it’s important to feed your fish only the amount they need, as providing too much food can lead to waste when the surplus decays in the water. Further exploration of this topic will be done soon.

There Are Too Many Fish in The Tank

Overcrowding your fish tank greatly increases the likelihood that some of your fish will develop ammonia poisoning. A higher concentration of ammonia in the water is a direct result of an increase in fish population. There will come a point when the nitrogen cycle can no longer remove ammonia from the tank if you keep adding fish. The result could be ammonia poisoning.

Filtration Problems

Perhaps you’re wondering what the filter in your aquarium has to do with ammonia poisoning. F They are also home to many helpful bacteria that run the nitrogen cycle. Ammonia in the water can’t be degraded into a less dangerous form without these microorganisms. Thus, if you are setting up an aquarium for the first time, you need to take extra care to ensure that the filtration system is installed properly.

Putting Unfiltered Tap Water Into the Tank

An easy way to poison your fish with ammonia is to introduce unfiltered tap water to the tank, which is a typical mistake made by inexperienced fishkeepers. The explanation for this is elementary. A large level of ammonia in untreated or untested water can cause serious problems in an aquarium, even threatening the lives of the fish inside.

pH Conditions That Aren’t Ideal

The health of your fish depends on several factors, and one of the most crucial is that the pH level in their tank is kept constant. Your fish’s health and the stability of the nitrogen cycle are both threatened by water with an excessively high or low pH. For the nitrogen cycle to break down completely, water pH must be kept above 6.

This prevents nitrate formation from the ammonia created by the digestion of fish and other food in the water.  Toxic levels of ammonia may result from doing so. To avoid this, keep the water’s pH in the ideal range at all times (between 7 and 8).

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What Are The Signs Of Ammonia Poisoning In Fish?

Ammonia poisoning can be fatal if not treated promptly; thus, familiarizing yourself with the warning symptoms is essential. A fish has a good chance of survival if you catch it quickly. Having said that, here are some common signs and symptoms:

Low Appetite

Fish that have been exposed to toxic levels of ammonia often show signs of loss of appetite. Ammonia poisoning is one of many potential causes if your fish have been ignoring their food. Fish may lose their appetite, appear listless and frail, and refuse to swim.

Keep in mind that there could be other causes for your fish’s lack of appetite besides ammonia toxicity. Therefore, it is important to keep an eye out for other symptoms.

Gill Inflammation

Inflamed gills are another sign of ammonia poisoning in fish. There is a high likelihood that your fish have ammonia poisoning if their gills are red or if there is visible bleeding from the gills. Toxic levels of ammonia can cause reddening and damage to the gills. It can also make the fish feel stressed, which can make their immune systems weaker.

Struggling for Air Near the Water’s Surface

You can tell your fish are under stress if you witness them gasping at the water’s surface. Many fish suffer from stress, which is bad for their health. High amounts of ammonia in the water are a possible stressor for fish. Fish that are beginning to show signs of ammonia poisoning may likely be seen gasping at the tank’s surface.

Changes in Body Color

The appearance of a change in skin tone is the next warning sign to look out for. A fish that has been poisoned by ammonia will look very different. One of the first symptoms is a reddening and possibly bleeding appearance of the gills, as we discussed above. This is a typical symptom of ammonia toxicity. Second, a fish’s body color may change, becoming darker, and even developing red streaks.

Slowed Movement and Reduced Activity

The decrease in activity and movement is the last symptom of ammonia poisoning in fish. A fish that has been poisoned by ammonia may become less active. It could appear listless and fatigued and stand still for long stretches of time. This is typically associated with ammonia toxicity and its associated immune system suppression and other health problems.

How Do You Treat Ammonia Poisoning In Fish?

Even while ammonia poisoning is extremely harmful and can result in a wide variety of life-threatening symptoms, a fish can make a full recovery. If there is no severe bacterial infection and no ammonia burns, a fish can recover from ammonia poisoning. Sick fish that are suddenly exposed to high amounts of ammonia in the water may not be able to recover from their illnesses and may perish.

Let’s have a look at some advice and treatments for ammonia toxicity in fish. Although there is no magic pill that will make your fish better overnight, there are steps you can take to speed up their recovery.

Identify the Root Cause of Ammonia Poisoning

If your fish have been poisoned by ammonia, this is the first and most critical measure you can take to save them. You can’t put a halt to the problem or discover a remedy if you don’t know what’s causing the high levels of ammonia in the water. Another reason this step is vital is that it will inform you exactly what you’re doing wrong. Always keep in mind that pinpointing the issue is of utmost importance.

Check the Water Quality and Replace It if Necessary.

Water testing and regular tank water changes are additional forms of treatment you can provide for your fish. Keep an eye on the ammonia levels in the water and replace it if they rise to unsafe levels. You’ll have to do it yourself because the nitrogen cycle isn’t cleaning up the water.

Be sure to check the quality of the tank’s new water before adding it. Another potential issue is that it contains a lot of ammonia.

Ensure Adequate Oxygen for Your Fish

It is difficult for a fish to breathe when its respiratory system has been attacked by ammonia. Fish suffering from ammonia poisoning may be seen gasping at the water’s surface. Use aquarium equipment like air stones and bubblers to make breathing easier for your fish in their tank. In addition to keeping the water moving, they make it easier for fish to breathe. Fish can breathe easier when the water in their tank is kept at a lower temperature.

Move the Sick Fish to a Different Tank

If you suspect that your fish have been exposed to toxic levels of ammonia, the first step in treating the problem is to isolate the sick fish in a quarantine tank. To be more precise, this is one of the very first things you should do. This will ensure the safety of your fish until you figure out what’s wrong with the old tank.

Remember that the secondary tank must also meet appropriate standards to ensure the fish’s survival. The nitrogen cycle needs to be set up, and there should be very little ammonia in the water.

Reduce the Amount of Food You Give Your Fish.

Reducing your fish’s food intake below its typical level is another vital step in assisting their recovery from ammonia poisoning. Ammonia production can be reduced by reducing the amount of food waste. Having fewer fish to dispose of also means less ammonia will be produced.

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How Do You Remove Ammonia In Your Fish Tank Naturally?

Fish should not be exposed to ammonia at any time. This is the leading cause of death for aquarium fish. A high concentration of ammonia in your aquarium necessitates prompt action. To help you get rid of ammonia in your aquarium without resorting to harsh chemicals, we’ve compiled a few natural solutions.

Fill the Fish Tank Partially with New Water

One simple method of reducing ammonia levels in a fish tank is to perform a partial water change. By replacing 30–50% of the tank’s water, ammonia can be greatly reduced.

The Fish Tank Should Be Cycled

Fish tank cycling is the practice of maintaining a healthy population of microorganisms in your aquarium. If you’re just getting started with aquariums, you might not realize that ammonia levels in the water need to be kept under control with the help of bacteria.

Fish should be removed from the tank six to eight weeks before beginning the cycling process. It’s as easy as stocking the hazardous water with plants and smaller fish like minnows and barbs to generate beneficial bacteria that consume excess ammonia.

Increase The Airflow In The Fish Tank

It is possible to reduce ammonia levels by a significant margin simply by increasing aeration, or the circulation of air and dissolved air throughout your tank’s water. This is due to the fact that fish tanks that have adequate aeration allow the dissolved gas ammonia to escape back into the air and out of the tank.

Upgrade Your Fish Tank’s Filtration System

A rise in ammonia levels will occur regardless of any measures taken to reduce them if the filter is malfunctioning. The filter pad should be clean for optimal performance. There may be too much ammonia being produced by your fish for a single filter to handle, so you’ll need to install a second filter.

Putting Live Plants in The Fish Tank and Taking Care of Them

One of the finest ways to naturally eliminate ammonia in a fish tank is with the help of a living plant. To flourish, plants require a wealth of nutrients, which are often provided by leftover fish and food. Actually, the ammonia levels in an aquarium can be kept in check by the presence of live plants.

The ammonia-generating components are removed by the plants, and the plant’s nutrient needs are met so that you don’t have to. On top of that, they generate oxygen for your fish to breathe.

Upgrade Your Fish Tank

A lack of water, vegetation, or filtration might lead to a toxic environment if there are too many fish in a small area. Think about upgrading to a larger aquarium for your fish. This will increase dilution and provide your anti-ammonia components, like filters and plants, with a better opportunity to do their job.

Put Some Good Bacteria in The Fish Tank

New fish tanks often contain alarmingly high levels of ammonia, making this the recommended course of action. Most likely, this is because your brand-new tank lacks the essential bacteria for maintaining a healthy water cycle. Taking components from a decommissioned aquarium and introducing them to a new one is a quick approach to incorporate healthy bacteria that will process the ammonia in the water.


Can A Fish Recover From Ammonia Poisoning?

If the fish does not have a severe bacterial infection and does not suffer from ammonia burns, it should be able to recover from the poisoning caused by the ammonia.

Does Water Conditioner Remove Ammonia?

Ammonia cannot be removed from water by using a water conditioner. Most water conditioners, on the other hand, neutralize ammonia by binding to it. The ammonia will still be present in the tank but in a non-lethal form.

Does Tap Water Have Ammonia?

The presence of ammonia in tap water supplies is not uncommon. The reason for this is the usage of chlorine and chloramine in municipal water systems for disinfection.

Do Air Stones Help With Ammonia?

The dissolved oxygen in your fish tank’s water can be improved with the help of an air stone by using it to generate tiny bubbles. If there is a lot of dissolved oxygen (DO) in your aquarium water, then the decomposing organic matter is less likely to produce poisonous ammonia, which can be toxic to fish.

Is Ammonia Poisoning In Fish Contagious?

Ammonia poisoning can result in significant bacterial infections and a host of other issues in fish, and in some cases, it can even be fatal for them.

Will Water Changes Cure Ammonia Poisoning?

In order to reduce ammonia levels, water changes are a simple and effective solution. Ammonia can be quickly eliminated from the fish tank by doing a water change, introducing clean water that will help dilute any lingering ammonia.

Can Ammonia Poisoning Turn Fish Black?

When exposed to high concentrations, ammonia is poisonous and causes severe skin burns both internally and externally. Fish affected by high amounts of ammonia exhibit behavioral changes as well as a blackening of their skin.

Can One Fish Die Of Ammonia Poisoning While Another Fish Is Fine?

Fish have mechanisms in place to protect them from the ammonia pulse that occurs after feeding, as well as from increases in external ammonia. As a result, fed fish are less susceptible to external ammonia than fish that have recently been fed. A variety of fish species may survive high levels of ammonia in the environment.


One of the most frequent and distressing illnesses your fish might suffer from is ammonia poisoning. It’s brought on by excessive amounts of ammonia in the water that the nitrogen cycle can’t process. Fish that have been poisoned by ammonia may die from bacterial infections and other problems.

Fish poisoning from ammonia can be avoided in a number of ways. Tank maintenance consists of periodic water changes, ammonia tests, and cleanings. We hope that you have found this information useful!

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