What is Ammonia Poisoning In Fish (& 6 Remedies)

Ammonia poisoning is a common illness that affects aquarium fish and can be a nightmare for fish keepers who’re new or inexperienced. No one wants to see their fish getting weaker and eventually dying.

So what are some causes of ammonia poisoning in fish? These causes include overfeeding, an overcrowded tank, inadequate filtration, failure of the nitrogen cycle to remove ammonia, and the introduction of untreated tap water to the tank.

Read on to find out more about ammonia poisoning in fish. Learn about its causes, symptoms in fish, and some measures you can take to prevent it from happening. Happy reading!

What Is Ammonia Poisoning?

If you’re somebody who’s new to fishkeeping and who’s recently set up their own aquarium for the first time, chances are you might be unaware of what ammonia poisoning is. Simply put, ammonia poisoning is when the water contains too much ammonia, and it starts negatively impacting the health of the fish.

In all aquariums, ammonia comes from many sources. These include fish food, fish waste, rotting plants, etc. Ammonia is harmful to fish and needs to be removed from the water to prevent the fish from getting sick. The nitrogen cycle, driven by beneficial bacteria, is what removes ammonia from the water by converting it into less harmful nitrites and nitrates. If the nitrogen cycle can’t remove ammonia from the water, the fish start getting sick, and some may even die.

Ammonia poisoning causes fish to develop many health problems, including inflamed gills and a loss of appetite. We’ll discuss more of these symptoms later in detail.

What Causes Ammonia Poisoning?

Ammonia poisoning in fish can occur due to a number of reasons, ranging from overfeeding to suboptimal pH levels. Here, we mention some of them.

1. Overcrowded Fish Tank

Having an overcrowded fish tank significantly increases the chances of your fish having ammonia poisoning. The reason for this is simple. The more fish you add to your tank, the more ammonia they’ll produce. If you keep on adding fish to your tank, the nitrogen cycle won’t be able to remove the ammonia at one point. This can then lead to ammonia poisoning.

Another important thing to keep in mind is to increase your aquarium’s population gradually if you’re starting fishkeeping and have a new tank. Adding fish one by one will allow the nitrogen cycle to keep up with the increased ammonia production.  

2. Nitrogen Cycle Hasn’t Been Established in the Tank

If the nitrogen cycle hasn’t been established in your tank, it can be a big problem for your fish. Fish food, rotting plants, and fish themselves produce a lot of ammonia, and removing it from the tank is important.

As we discussed previously, the nitrogen cycle plays a vital role in maintaining ammonia levels inside the tank and prevents nitrogen poisoning in fish. In the nitrogen cycle, healthy bacteria decompose ammonia into less harmful substances such as nitrites and nitrates.

Letting the nitrogen cycle build up in your tank is known as “cycling.” Cycling is done by setting up your aquarium, turning on the filter, and adding ammonia to the water. At one point, if you test your water, it will show no amount of ammonia. This means the nitrogen cycle has been successfully established in your tank.

A green beautiful planted tropical freshwater aquarium with fishes

3. Overfeeding Fish

Overfeeding fish can cause a whole lot of problems, from health problems in fish to environmental problems in the tank. But how exactly does overfeeding lead to ammonia poisoning in fish? The answer is simple: fish food produces ammonia when it starts rotting. This is one mistake beginners often make. They put more food than the fish need and thus lots of food remains uneaten in the tank and starts to rot.

This is why it is a good idea to feed your fish just the right amount of food to prevent excess food from rotting in the water. We’ll discuss more about this in later sections.

4. Inadequate Filtration

You might be wondering what the filter of your aquarium has to do with ammonia poisoning. The answer might surprise you. Interestingly, filters don’t protect your fish by removing waste from the water. They’re also home to many beneficial bacteria that effectively run the nitrogen cycle. And without these bacteria, there’s no way the ammonia in the water can be converted into something less harmful. So, it is important to install your filtration system correctly and carefully if you’re setting up an aquarium for the first time. It is home to the little defenders that protect your fish from ammonia poisoning.

5. Introducing Untreated Tap Water to the Tank

Introducing untreated tap water into the tank is a fairly common mistake beginners with little experience make and one that is likely to cause ammonia poisoning in your fish. The reason for this is simple. Untreated and untested water can likely contain a high amount of ammonia which can wreak havoc in your aquarium, putting the lives of your fish at risk.

Ammonia in untreated tap water usually makes its way into your aquarium when you do a water change. Even if you use tap water you consider to be clean and safe, it can contain ammonia and other harmful chemicals you aren’t aware of. There is, however, a way to change water safely, which we’ll discuss later.

6. Suboptimal pH Conditions

Maintaining optimal pH levels in your fish tank is of paramount importance since it ensures the well-being of your fish in many ways. If the pH of the water is too high or too low, it can disrupt the nitrogen cycle and also negatively impact the health of your fish. 

If the pH of the water is too low (below 6), it can cause the nitrogen cycle to stop working altogether. This means that the ammonia produced by the fish and food in the water will not get converted into nitrates. This can lead to ammonia poisoning. To prevent this from happening, the pH of the water should always remain in the optimal range (between 7 and 8).

Symptoms Of Ammonia Poisoning In Fish

We’ve looked at the main causes of ammonia poisoning in fish but knowing the causes only won’t help you much. You also need to know the symptoms of ammonia poisoning in fish so that you can act promptly. Here are some symptoms that you need to watch out for.

1. Reduced Appetite

A reduced appetite is one of the most common symptoms of ammonia poisoning in fish. If your fish have been leaving their food alone recently, one of many reasons behind that may be ammonia poisoning. You might observe the fish becoming uninterested in eating and appearing lethargic and weak.

One thing to keep in mind is that your fish might have less appetite for other reasons besides ammonia poisoning. So watch out for other symptoms as well.

2. Inflamed Gills

Another common symptom in fish suffering from ammonia poisoning is inflamed gills. If your fish appear to have red gills or gills that seem to be bleeding, chances are they’re suffering from ammonia poisoning. In severe cases of ammonia poisoning, it is common for the gills to become red and get damaged. It can also cause the fish to become stressed and can weaken their immune systems.

3. Gasping Near the Surface of the Water

If your fish can be seen gasping near the surface of the water, they’re likely stressed. Stress commonly affects many fish and can be detrimental to their health. One reason for fish getting stressed can be high levels of ammonia in the water. If the ammonia starts affecting the health of the fish, you may see them gasping near the surface of the tank’s water.

4. Change in Body Color

The next symptom that you need to keep an eye out for is a change in body color. If a fish has ammonia poisoning, its body will have a different appearance. Firstly, as we mentioned earlier, the gills will turn red and may appear to be bleeding. This is quite common in cases of ammonia poisoning. Secondly, the body color of a fish may darken and you may even observe red streaks on the body.

5. Reduced Activity and Motion

The last ammonia poisoning symptom in fish we’ll be talking about is a reduction in activity and movement. If a fish is suffering from ammonia poisoning, you may notice a reduction in its physical activity. It might appear to be lethargic, and tired, and may remain motionless for extended periods. This is usually linked to a weakened immune system and other health complications caused by ammonia poisoning.

Can A Fish Recover From Ammonia Poisoning?

We now know some of the causes and symptoms of ammonia poisoning in fish. Something you might be wondering about is: can a fish recover from ammonia poisoning? The answer is yes, fortunately. While ammonia poisoning is a dangerous condition that brings about many serious health problems, a fish can fully recover from it.

A fish can recover from ammonia poisoning if it doesn’t have a serious bacterial infection and doesn’t suffer from ammonia burns. In such a case, although the fish needs to be quarantined initially, it can be put back in the old tank after a week or so. But fish can also die from ammonia poisoning. Fish that have severe infections and are exposed to sudden increases in ammonia levels in the water might not recover from their conditions and are unlikely to survive. 

To sum it up, a fish can only recover from ammonia poisoning if the nature of the infection isn’t serious.

How To Treat Ammonia Poisoning In Fish

We’ve talked about the causes of ammonia poisoning as well as some symptoms you can watch out for. Now let’s have a look at some tips and ways of treating fish suffering from ammonia poisoning. While there’s no solution that can instantly cure your fish, there are some things you can do to make it easy for them to recover.

1. Find Out the Reason Behind Ammonia Poisoning

This is the first and most important step in treating your fish if they have ammonia poisoning. If you don’t know the source of the excess ammonia in the water, you can’t stop the problem and find a solution. We’ve previously mentioned the 6 main causes of ammonia poisoning, so make sure you know what they are. 

Another reason this step is important is that it will tell you exactly what you’re doing wrong. Is your tank overcrowded? Are you using untreated tap water? Is your filtration system faulty? Remember, identifying the problem is of paramount importance.

2. Conduct Water Tests and Change the Water

Another thing you can do to treat your fish is to change the water of your tank and conduct water tests frequently. You should monitor the ammonia levels in the water at regular intervals and change the water whenever the levels get high. Since the nitrogen cycle isn’t doing its job of removing ammonia from the water, you’ll have to do it yourself.

One thing that you have to be careful about here is to test the new water you’ll be putting into the tank as well. It might also have high ammonia levels and that can worsen the problem.

3. Make It Easy for Your Fish to Breathe

Ammonia poisoning attacks the respiratory system of a fish and makes it difficult for it to breathe. It can even cause permanent damage to the respiratory system. This is why you may see a fish gasping near the surface of the water if it has ammonia poisoning. To make it easy for your fish to breathe, you can use bubblers and air stones in the tank. They keep the water flowing and put less burden on the respiratory system of a fish.

Keeping the tank water cooler can also help your fish breathe easily.

4. Shift the Affected Fish to a Separate Tank

Once you realize your fish are suffering from ammonia poisoning, it is a good idea to shift the affected fish to a separate tank and quarantine them. In fact, this is one of the first steps you should take. This will give you time and space to figure out the problem in the old tank and will also keep your fish safe.

Do keep in mind that the second tank also has to be safe enough for the fish to live. The nitrogen cycle must be established and the ammonia levels in the water should be really low.

5. Reduce the Amount of Food You Feed Your Fish

Another important step you can take to help your fish recover from ammonia poisoning is to feed them less food than you normally do. Less food means less of it will be left over and thus less ammonia will be produced. It also means less fish waste, which again results in less ammonia production.

It is important to note that this should be a temporary change done only to get the ammonia levels in the water under control. Once that happens, you can resume feeding your fish normally like before.

How Fast Does Ammonia Poisoning Kill Fish?

So, how fast does ammonia poisoning kill fish? The answer to this isn’t definite and depends on how sick the fish is. For fish that are lucky enough to be mildly sick, they can make a full recovery within a couple of weeks. But for fish with severe infections and ammonia burns, surviving might not be a possibility and they can die within a few days. 

Again, how long a fish survives after getting sick depends on the ammonia levels in the water and the severity of its infection. In some cases, a fish may have a prolonged illness and might die a week or two after being infected if the toxic ammonia conditions in the water persist. And if the amount of ammonia in the water keeps on increasing rapidly, then the fish might die quickly. The longer the fish is exposed to high ammonia levels, the quicker it will die.

How to Prevent Ammonia Poisoning

Previously, we looked at some tips and ways of treating ammonia poisoning in fish. While those are quite helpful, it is better to be able to prevent ammonia poisoning from happening in the first place. Here are some ways to do just that.

1. Establish a Beneficial Bacteria Colony and the Nitrogen Cycle

The first step in preventing ammonia poisoning in fish is to set up your aquarium correctly and carefully so that beneficial bacteria are present in the water and the nitrogen cycle gets established. This is important to keep ammonia levels in the water down.

To do this, ask your local fish store to help you set up your aquarium. They usually do this by giving you water and gravel from an already-established aquarium. This helps in making the water in your aquarium suitable for fish. You shouldn’t add fish to the tank until the nitrogen cycle has been completely established though.

2.  Avoid Overfeeding Fish and Overcrowding the Tank

These two preventive practices are really simple. You should feed your fish only as much food as they need, and you shouldn’t make your tank overcrowded by adding more and more fish. Overfeeding fish and overcrowding the fish both contribute significantly to the total ammonia production in the water. The more leftover food and fish you have in the tank, the more ammonia will be produced.

And of course, if there’s too much ammonia in the water, it can’t be removed by the nitrogen cycle. Which will then lead to ammonia poisoning in fish.

3. Clean the Tank Regularly and Change the Water

Cleaning your fish tank and changing its water regularly is something that should be done all the time, not only when a problem arises. Many beginners make the mistake of skipping cleaning and maintenance and have to deal with a host of problems later as a result.

When you clean your tank regularly, you also remove fish waste, leftover food, and other pollutants. This helps keep ammonia levels in the water down. Changing the water on a regular basis is equally important and helps keep the amount of ammonia under control.

4. Conduct Water Tests for Ammonia Frequently

Besides cleaning your fish tank and changing the water regularly, you should also test the water frequently to check the ammonia levels. This is good practice for keeping an eye on the amount of ammonia in the water and taking prompt action if there seems to be a problem.

Doing this allows you to take action to reduce ammonia levels in the water before the fish start getting sick. It helps you prevent ammonia poisoning and is one of the most important preventive measures to take.

5. Maintain an Optimal Water PH

As we mentioned before, maintaining an optimal pH is important for a variety of reasons. It keeps the fish healthy and allows the nitrogen cycle to function properly and converts ammonia into less harmful substances. If the pH gets too low, it can affect the nitrogen cycle and make the bacteria incapable of removing ammonia from the water.

Remember, the optimal pH range is between 7 and 8. There are several ways you can maintain the pH of the water, including putting acid or alkaline buffers in the water depending on the pH conditions.

Final Thoughts

Ammonia poisoning is one of the most common and painful ailments that can affect your fish. It is caused by high levels of ammonia in the water that can not be removed by the nitrogen cycle. Ammonia poisoning can cause serious bacterial infections in fish among other complications and may even prove to be fatal for them.

There are quite a few ways you can prevent ammonia poisoning in your fish. These include regularly cleaning your tank, testing ammonia levels in the water frequently, and changing the water. We hope you found this guide helpful!