14 Signs Your Fish Is Dying & Is It Suffering?

Last Updated on 2023-12-17

Not sure if your fish is dying or not? If so, you’ve found the right article! Not only will you find out if your fish is dying or not, but you’ll also find out whether it’s possible to save them or not, depending on what’s wrong with them!

With that being said, keep reading to find out everything you need to know!

Key Takeaways:

  • Fish can experience pain and suffering, so it’s important to be aware of signs that your fish may be dying.
  • Common signs of a dying fish include gasping for air, high breathing rate, pinecone scales, swollen belly, swimming sideways or upside down, and more.
  • Addressing water quality issues, diseases, and poor nutrition are key to potentially saving a fish showing these symptoms.
  • Euthanasia should be considered as a last resort when a fish is suffering and there’s no chance of recovery.
  • Regular monitoring of water quality, temperature, and stress factors can help prevent common causes of fish health problems.

Do Fish Suffer When They Die?

Fish can experience pain so if your fish is dying from an illness or disease, then they are most likely suffering. If you know that there is no chance of recovery for your fish, then you should consider euthanasia.

Signs A Fish Is Dying

If you think that your fish is dying, here are the most common symptoms to look for. Fortunately, some of them are treatable, and you may be able to save them even if you notice the symptoms!

Before you read on though, here is a helpful table so you can troubleshoot the issue quickly!

Gasping for AirPerform an immediate water change, test for ammonia levels, and consider adding API Ammo Lock.
High Breathing RatePrioritize water change and check for diseases.
Pinecone ScalesEuthanasia is often the only humane solution, as it’s most likely dropsy.
Swollen BellyCheck for constipation, swim bladder disease, or dropsy.
Swimming Sideways/Upside-downWater change, dietary changes, and test water parameters.
Stopped EatingQuarantine and diagnose for illnesses.
Fading ColorCheck light exposure and diagnose potential illnesses.
Weight LossDiagnose the underlying issue, starting with constipation.
Gills Changed ColorImmediate 50% water change and test ammonia levels.
Erratic SwimmingWater change, varied diet, and consider diseases.
White Spots on BodyUse API Liquid Super Ich Cure for Ich treatment.
Gills Stopped MovingImmediate action with water changes and aeration.
Redness on BodyAdminister antibiotics and conduct frequent water changes.
Cloudy EyesCheck water parameters and consider bacterial infection.

Gasping For Air

One common sign that a fish is dying is that it’ll be gasping for air. If your fish is gasping for air, it could be caused by the following:

  • There’s not enough oxygen in the water.
  • The water is high in ammonia.
  • They are suffering from a disease such as ich, columnaris, anchor worms, or gill flukes.
  • The tank is too crowded.
  • The temperature in the tank is too high.


As you can see, there are a few different reasons that your betta may be gasping for air. So if you see it in your tank, the first thing you should do is perform a water change to get some fresh water back into the tank. Which will solve a lot of the problems temporarily

  • First of all, if the ammonia was too high before, it should return to a safe level.
  • If there wasn’t enough oxygen in the tank before, adding new water will increase the amount of oxygen in the tank.
  • And if the temperature in the tank is too high, as long as you’re adding water that’s cooler, then the temperature will drop (just make sure the temperature isn’t dropping too rapidly, or they could end up suffering from temperature shock).

Once you’ve added new water, you can then work on permanent solutions for your fish. If the tank is overstocked, consider purchasing a bigger tank or moving fish into another tank. Remember, a good rule of thumb is 1 inch of fish per 1 gallon of water.

If the ammonia is too high, you can perform more frequent water changes and add API Ammo Lock to neutralize any ammonia.

When the temperature is too high, you can check the heater and thermometer in the tank and replace either if they’re faulty. In cases when it’s just too hot, you can also let a fan blow over the tank to make sure it stays cool.

And if you think your fish is suffering from a disease, you should diagnose the symptoms and treat them accordingly.

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High Breathing Rate

Your fish may not be gasping for air, but they may still have a high breathing rate. Once again, the most likely cause of this is poor water conditions, although some diseases may cause this to happen as well.

If you notice that your fish is producing more mucus, especially around the gills, then disease or parasites could be the problem. Otherwise, the water quality in the tank could be too poor.


Once again, changing the water should be your first priority, and then after that, you can figure out whether the tank has too much ammonia, not enough oxygen, poor water conditions, etc., and act accordingly.

Pinecone Scales

Sadly, if you notice that your fish has pinecone scales, then the chances of their survival are slim to none. Pinecone scales are a clear sign of dropsy, and if your fish is suffering from dropsy, normally, the best solution is euthanasia.

If you’re not sure what pinecone scales look like, it’s when the scales of your fish stick out after the fish becomes swollen. Dropsy is normally caused by a build-up of infection and damage inside your fish. And if they are suffering from it, at this point, the damage is normally irreversible.

Swollen Belly

If your fish has a swollen belly, it’s a good indicator that they could be suffering from dropsy, especially in cases where their scales have pineconed too.

However, don’t rule your fish out just yet if they’re only suffering from a swollen belly. Constipation and swim bladder disease could also be reasons your fish has a swollen belly too!

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Swimming Sideways Or Upsidedown

Another sign that your fish could be dying is if they’re swimming sideways or upside down. Fortunately, in some cases, they can still be saved, but in other cases, it could already be too late.

The most common reason that a fish could be swimming like this is due to swim bladder disease. This occurs when the swim bladder of the fish is damaged. Constipation, injury, diseases, and parasites can all be behind this, but if you catch it early, you should be able to fix it.


If you think that your fish is suffering from swim bladder disease, then you should change the water to improve the quality. Once this is done, you can then work on the individual issues.

  • If fish are suffering from constipation, often feeding them a deshelled pea or brine shrimp (depending on their diet preference) can get their digestive system moving again. On top of this, you can also fast them for a couple of days.
  • However, if you think that poor water quality is behind the swim bladder disease, you should perform water changes more often, testing the ammonia, nitrites, and nitrates regularly to make sure they’re low enough.
  • And lastly, if you think that the fish has been injured, there’s not much you can do. If possible, move them to a quarantine tank with no sharp objects. If you can’t do that, take any sharp objects out of the tank, and make sure there’s nothing else they can hurt themselves on either.

They’ve Stopped Eating

One of the first signs that something is wrong with your fish and that they could potentially be dying is when they stop eating. A lack of appetite is most often caused by an illness or disease of some kind; however, sometimes, it can just be old age.

Either way, a lack of appetite and not eating at all can be a sign that your fish is starting to die.


If you think your fish has stopped eating because they’re sick, then you should try to diagnose the sickness as soon as possible and treat them accordingly. In the meantime, though, it’s a good idea to move them to a quarantine tank if possible. And if not, performing a water change to make sure the water is as clean for them is also a good idea.

Their Color Is Starting To Fade

Another sign that your fish is potentially dying is when its color begins to fade. If your fish has dull colors, then it’s often a sign of infection or age. However, fortunately, fading color doesn’t always mean your fish is going to die. In fact, sometimes, the fading color just means that your fish hasn’t been getting enough light.


If your fish’s color is beginning to fade, then you should figure out whether it’s because they’re sick or because they’re not getting enough light. If it’s the latter, the solution is simple; just make sure you’re keeping them in the light for longer.

However, if their color is fading because they’re sick, then you’ll need to diagnose the illness and treat it accordingly. In many cases, if the color has only just started to fade, your fish can still recover if they’re treated!

Weight Loss

If your fish has lost a lot of weight, it’s another clear sign that they’re dying or something is seriously wrong. Fish are extremely gutty, so if they don’t want to eat, there’s a reason for it.

Some ways to tell if your fish is losing weight is by looking at their things, such as how they swim and if they’re eating. If you notice they’re not swimming properly anymore or not eating a lot, then something is definitely up.


The best way to help them recover from this is by diagnosing whatever is wrong with them in the first place. There are all sorts of diseases that can make your fish want to stop eating. But constipation is the best place to start as this tends to affect their appetite quickly.

Their Gills Have Changed Color

Another extremely bad sign that your fish is dying is when its gills have changed color. If the gills have turned brown or black, then it could be a sign that the cells have died. The most likely reason behind this is ammonia or nitrite poisoning; however, it could also be certain diseases.


If you notice that your fish’s gills have changed color, then you should immediately perform a 50% water change. After doing that, repeatedly test the water. If you notice the ammonia or nitrite levels rising, perform another water change.

Once again, you can also use API Ammo Lock to neutralize the ammonia in the water as well.

Erratic Swimming

If your fish is swimming erratically, there are a whole bunch of causes behind it, and none of them are good. Some of the reasons that your fish may be swimming erratically include:

  • Swim bladder disease.
  • Nervous system disorders & neurological damage.
  • Parasites
  • Poor nutrition
  • Hypoxia
  • Poor water quality


If you catch your betta swimming erratically early, there are a few things you can do to get them back to full health.

The first thing you should do is perform a water change. This way, you’re going to improve the water quality dramatically. Once you’ve done this, keep testing the water to make sure the parameters are fine.

If you think poor nutrition is behind your betta swimming erratically, then you should consider giving your fish a more varied diet. If you’re only feeding them flakes or pellets, try mixing things up and giving them live food or blanched vegetables as well (depending on their food preference)

When you think hypoxia is behind them swimming strangely, then adjust the filter so it causes more ripples on the surface. As well as this, add an air bubbler or plants to the tank as well to increase oxygenation.

Lastly, if you think your fish is suffering from an illness or disease, then move them to a quarantine tank. When you’re there, feed them well and treat them as best you can.

White Spots On Their Body

White spots appearing on your fish’s scales can indicate a parasitic infection, commonly known as “Ich.” This ailment is a serious concern and could lead to a fish’s death if not treated promptly. 


The key to managing this condition is early diagnosis and medication specifically designed to treat Ich such as API Liquid Super Ich Cure

Their Gills Have Stopped Moving

Inactive or slow-moving gills are a critical sign that your fish is struggling to breathe. This could result from poor water quality caused by a build-up of ammonia, or a lack of oxygen.


Immediate action is needed, like water changes and perhaps additional aeration, to help the fish breathe more easily. If you notice your fish struggling to breathe, you should also test the wate right away to see what the parameters in the tank are.

Redness on Their Body

Red patches or streaks on the body of the fish usually signify bacterial infections or high levels of ammonia in the water, especially when the redness is by the gills. Both of these conditions are severe and need urgent attention.


Treating the water and possibly administering antibiotics are the first steps in addressing this issue. As well as that, frequent water changes and keeping an eye on the parameters in the tank are also essential.

Cloudy Eyes

Cloudy or discolored eyes often signify an underlying health issue, potentially indicating a bacterial infection or poor water conditions. In some cases, it could also be due to physical trauma. 


Again, the first thing you’ll need to do is make sure that the water parameters in the tank are adequate. Once you’ve done this, you may also need to administer medication. 

In cases where only one eye is cloudy, then it could be caused by trauma, in which case you’ll just need to let your fish rest.

Dramatic Weight Loss

If your fish exhibits significant weight loss or appears visibly thinner, this could be due to malnutrition or internal parasites. 


Both scenarios require immediate intervention. The fish may need a specialized diet or medication to deal with parasites.

How To Tell When A Fish Is Dying Of Old Age

Sometimes your fish will simply be dying of old age, and there’s nothing you can do about it! If you’ve had your fish for a few years, then this is probably going to be the case. When a fish is dying from old age, you’ll notice the following symptoms.

Poor Appetite

If your fish doesn’t eat as much as they used to and they’re getting old, then it’s a sign that their life is coming to an end. When they refuse to eat completely is typically the sign that there aren’t going to be many days left.


The older your fish gets, the less they’re going to move around as well. When your fish is close to dying, you may notice that their movement has become minimal.

Loss Of Color

As their bodies get weaker and weaker, you’ll begin to notice that your fish looks a lot more faded, and the colors won’t pop as they used to. Again, there’s nothing you can do about this; it’s just a sign of old age.

Common Causes Behind Your Fish Dying

While there are plenty of specific reasons that your fish may have died, here are the most common causes behind them. These are the ones you can keep on top of from the beginning to prevent your fish from getting sick!

Poor Water Quality

The quality of the water in your aquarium is key yo the well-being of your fish.

Suboptimal water conditions, such as high levels of ammonia, nitrites, or nitrates, can have adverse effects on fish health. These harmful elements can impair the fish’s gills and internal organs, leading to increased susceptibility to diseases.

Regular water testing and changes are essential for maintaining optimal water quality. Failing to do so can result in loss of fish life.

Wrong Water Temperature

Temperature plays a crucial role in the metabolism and immune system of tropical fish.

A water temperature that’s too high can lead to increased metabolism but decreased oxygen levels, making it difficult for fish to breathe. Conversely, a too-low temperature can slow down a fish’s metabolic processes, making them vulnerable to infections.

Generally, most tropical fish require a consistent water temperature within a specific range, usually between 75 and 80 degrees Fahrenheit (24–27 degrees Celsius).


Fish are susceptible to stress from various sources such as sudden changes in water conditions, overfeeding, and bullying from other fish. Chronic stress weakens the fish’s immune system, making them more prone to diseases and infections.

Signs of stress may include erratic swimming, decreased appetite, or faded colors. It is vital to identify and mitigate the source of stress as quickly as possible to ensure the longevity of your aquatic pets.

Poor Diet

Although dietary needs are species-specific feeding your fish an incorrect diet can lead to malnutrition or obesity, both of which are harmful to your fish.

Malnutrition impairs the immune system and the ability to heal, whereas obesity can lead to blockages like constipation and swim bladder disease.

Ensuring a balanced diet rich in the necessary nutrients, vitamins, and minerals will help in maintaining the overall health of your fish.

What To Do When Your Fish Is Dying

Navigating the difficult time when your fish is dying can be stressful. But understanding the appropriate steps to take, from water changes to medication and, in severe cases, euthanasia, can make a significant difference in the quality of life that your fish can have. Here’s a breakdown of what you should consider.

Water Changes

The first step when you notice your fish looks like it’s dying is to test the water parameters immediately. If the pH or temperature isn’t right, ammonia and nitrites are too high, then this could be causing problems.

So use a reliable water testing kit like the API Master Tet Kit to assess these factors. If anything is off, work to fix the issues.

If the ammonia is too high perform a water change or add API Ammo Lock, if the pH isn’t right add pH Up or pH Down (or natural additives) and if the temperature is too high or low, the adjust your heater!


Remember, before you add medication you should always consult with a vet or professional. With that being said, they may recommend that you treat your fish with common medications like antifungals or anti bacterials.

The correct choice will depend on the symptoms of your fish, and remember to always follow the instructions.


Euthanasia should be a last resort, only considered when the fish is in irreversible pain and suffering. If you’re not sure whether it’s time to euthanize your fish, then you should always consult a professional first.

Humane methods include the clove oil method or the use of specific veterinarian-recommended medications designed for this purpose. And if you have children, make sure you understand the ethical and emotional implications before proceeding.


Here are some frequently asked questions people have about signs of dying in their fish!

How to Tell If Your Fish is Dead?

Your fish is likely dead if it’s floating motionless, often upside down, and doesn’t respond to stimuli like food or light changes. Additionally, the gills may stop moving, and the eyes often lose their clarity. It’s crucial to remove dead fish from the tank to prevent water contamination.

Do Fish Float or Sink When They Die?

Fish can either float or sink when they die, depending on various factors like water conditions and the reason for death. The biggest factor is how long the fish has been dead. Fish that have been dead for a while tend to float due to gasses produced by decomposition.

How Do You Know If a Fish Is Struggling?

Signs that a fish is struggling include erratic swimming, scraping itself on objects, rapid gill movement, and color changes. Also, changes in eating habits and a general lack of energy can be indicators. If you notice these signs, it’s essential to check water parameters and consult a vet.

Do Fish Die of Old Age?

Yes, fish can die of old age, although it’s less common in domestic aquariums due to factors like disease and stress. Old age in fish manifests as a decrease in activity, slowing metabolism, and a higher susceptibility to diseases. Maintaining a stable environment can help extend a fish’s lifespan.


As you can see, there are a whole bunch of signs that show when your fish is dying. But fortunately, in a lot of cases, if you notice the signs early enough, you can help your fish make a full recovery!

If you liked this article, make sure you check out the rest of the website! Otherwise, have a great day!

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