10 Signs Your Fish Is Dying (& What To Do)

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!

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!

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.

A green beautiful planted tropical freshwater aquarium with fishes

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!

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.

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.

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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!