Why Fish Keep Dying: 15 Common Causes and Their Proven Solutions

Why Fish Keep Dying

You got a new fish. But it perished overnight. Alas! New and even old ones face the sad moment when their new mate perishes suddenly. Why does it happen?

Everyone is perplexed to know why fish keep dying. Every fish keeper must understand the causes and their prevention method to give their fish a proper and healthy life.

Here is the comprehensive blog post that will answer all your questions. Also, make yourself an expert at fish keeping, knowing all prevention methods.

So, let us start on the journey.

Top 15 Causes for Why Fish Keep Dying And Ways to Prevent Them

Every aquarist, mostly new ones, faces the sudden death of their pet fish. But can a fish perish without any apparent reason? No! No matter how perplexing it might be to identify the reason, there will always be one that causes your fish to die.

The reasons can be many, ranging from the transfer, diet, and water condition to low maintenance. So here are the final 15 causes your fish is dying suddenly.

More than finding the causes is required to save your fish. You must know how to prevent them. For every reason, there is a prevention method. So, let us start. 

1. Poor Water Quality and Unsuitable Water Parameters

Water is the home of fish. If it is not proper, how can it survive? Think about that for a minute.

When a fish perishes suddenly, poor water quality can be the cause. Aquarium water can be saltwater, increased or decreased pH level, poisoning water, filtration efficiency, or other factors that can make water unsuitable. 

Knowing about these parameters is essential for a fish to live or perish. Water quality parameters are: 

  • Saltwater Aquarium 
  • pH level
  • Nitrite and nitrate level
  • Filtration efficiency 
  • Other water quality factors, such as hardness or poisoning. 

Note: Water quality is the first and foremost cause for fish to live happily or perish suddenly. However, every fish has its water parameters that must be maintained ideally.

How to prevent it?

Consult a vet or research a particular fish’s ideal water parameters. Maintain them as prescribed to ensure your pet fish’s safe and secure healthy life. 

Always check water quality through kits and measure its hardness, pH level, nitrite, and nitrate levels, and do check filtration efficiency for your fish’s ideal levels.

2. Poor Tank Conditions

Poor tank conditions can suddenly cause the death of fish. A fish cannot survive, even for hours, if tank conditions are not to their mark. 

Poor tank conditions include imported water temperature, insufficient plants and hiding spaces, low-sized tanks, cloudy water, improper water parameters, and algae or other toxic ingredients.

The presence of this single factor can slay a fish.

How to Prevent It? 

To make tank conditions ideal for the fish, first know about the needs and requirements of the fish. When you get information, fill your tank with essential elements.

Get a proper tank, set temperature, water parameters, and plants, gravel, and rocks. Do water and filter changes weekly. Clean algae by hand. Even fish are algae eaters. 

3. No Fish Acclimation

If a fish cannot acclimate to the new environment, it might perish within hours. If not hours, in days surely.

But what is the reason?

Fish live in their desired places with their chosen mates. Rapid water changes, temperature changes, tank mates, and other factors can be the causes.

When a fish is not trained, it will not acclimate. And perish suddenly.

How to prevent it?

Acclimating fish by raising water changes slowly. Add friendly tank mates. Keep the environment the same because it cannot face total change.

4. Low Maintenance

Low maintenance of the tank can cause fish to perish suddenly. A tank can be said to be low-maintained when:

Water is cloudy

Waste and uneaten food are present

Nor proper filter system

Absence of temperature maintenance system, etc

Fish live in their preferred environments. You will surely lose your pet friend if you do not heed their needs and requirements. No matter if the fish is new or old.

How to prevent it?

For a well-maintained ecosystem, add some algae eater fishes, clean the water properly, do water changes, install a filter system, and maintain temperature and other water parameters to desired levels.

5. Wrong Fish Ecosystem

Other causes, such as the wrong fish ecosystem, can also cause your fish to perish on the spot. If the fish is new, it certainly will.

Water temperature, plants and rocks in it, a mixture of toxic substances, and increased pH and hardness of the water can be the wrong fish ecosystem.

How to prevent it?

Research for a suitable environment for your fish. Maintain the required ecosystem for a healthier fish life. 

6. Illnesses

Why Fish Keep Dying

Illness can slay fish suddenly. It might be the cause of your fish dying.

Illnesses can be cured if identified on time. But, if you fail to recognize the sickness on time, you will know it when your fish perishes.

But some diseases can never be cured. They are ich, dropsy, fin rot, swim bladder diseases, and flukes. If you find any of these, the final spot is euthanizing.

How to prevent it?

Do monthly checkups to identify the disease. Always feed vitamin-rich food. And keep your fish away from toxic environments and ill fish.

7. New Tank Syndrome

The new environment haunts everyone. And fish are no exception. If everything is okay, but your fish perish. It can be due to new tank syndrome.

Many fish are set to a particular place. When they are transferred to another place, it causes stress, illness, and low eating. This factor is called new tank syndrome.

How to prevent it?

Maintain the same environment as the first one. Fill your tank with proper plants and decorations so fish live happily.

Make sure the tank mates are similar to the first home to cure new tank syndrome.

8. Old Age

No fish lives forever. It can perish suddenly the next day when it reaches a lifespan. There is no escaping to old age.

To properly care for your old friend, feed it properly, make its environment peaceful, and properly medicate it. These factors give a calm ending.

How to prevent it?

You simply cannot.

9. Poor Feeding Habits

Continuous poor feeding habits can lead to the death of fish suddenly. But what are the poor feeding habits? 

Poor feeding can be overfeeding or lower feeding. Or it can be a perish without proper vitamins.

Fish do not need three meals a day. It will only result in waste. Improper food can weaken their respiratory system and cause their belly to float.

Fish only need a few mouthful feeds for a day. Even if they demand, do not feed them.

How to prevent it?

Research the perish of all your fish. Feed them only prescribed food a few times. If a fish is weak, keep it aside and only feed it a few more times so it gains energy. 

10. Toxins from External Sources

External toxins can be fatal for fish on the spot. Even small amounts of toxins, such as big sprays, perfume, soap, lotion, cleaning chemicals, and other materials, can cause fancy and hardy fish.

If fish do not perish due to external toxins, water will surely become toxic. Resultantly, the fish will die suddenly. 

How to prevent it?

Keep aquariums away from any toxins. If a drop of toxin mixes in water, change water gradually.

11. No Lids

A water tank without lids can also cause fish to perish quickly. An aquarium without lids can be subject to a toxic mixture.

Waste can enter it, insects can enter the water tank, and other hated external resources can hamper overall water quality. As a result, fish will perish.

 How to prevent it?

 Always use a lid for your water tank. Drop off the lid under constant surveillance if your fish needs an open surface.

12. Agitation During Transport and Certain Movement

Unsuccessful transfer of the fish can slay it suddenly. Agitation during transport and certain moments can slay fancy fish on the spot.

Unsuccessful transfer can be said to:

  • High temperature of the water or pot
  • The small size of the pot
  • Inconvenience during transport
  • Less water in the transferring pot

However, if you put the fish in your perfectly balanced aquarium, agitation caused during transport will not leave.

13. Stress

Stress is the real fish serial slayer. Fish perish suddenly when they are facing stress. It cannot be identified easily, making it the most common cause of fish dying.

Stress can be due to unsuitable water conditions, improper water conditions, bullying tank mates, or unfitting aquariums. Also, under-sized tanks and poor territorial issues can result in stressful behavior.

But how do we know if fish are under stress? 

A fish shows different behaviors under stress. A stressed fish surfs around the glass, hides most of the time, is ill, or loses weight continuously.

How to prevent It?

While selecting a fish, keep its tank mates in mind. Keep the fish with tank mates that are friendly to it.

Other than that, fill your tank with plants, rocks, and other mandatory equipment to give a fish a natural look.

14. Prior Problems with The Fish

You come home with your pet fish. Transferred it properly. Set the aquarium to its parameters and put it with its friendly tank mates. But it perished, even though everything was perfect. 

How stressful is it? 

A fish can perish suddenly when water conditions are okay, only when it has a prior illness or disease. Previous problems with the fish can also slay fish quickly. And you cannot do anything.

How to Prevent it?

Always check properly before buying a new pet fish. Consult a doctor, and make sure the fish has no prior problems. If it has curable problems, cure them properly before putting them in your aquarium. 

15. You didn’t properly set up your aquarium

You got an aquarium, filled it with water, set up gadgets, and put a fish in it. Is that all? Will your fish survive? 

Not at all!

When a fish perishes suddenly or keeps dying, it might be due to improper aquarium preparation.

New aquarists majorly face this issue. They need to learn more about tank preparations. And later face continuous fish dying issues. Do you hate it?

Surely you will do. But how to prepare an aquarium? 

Before getting a fish, knowing about all the essential aquarium kits, gadgets, and organisms is mandatory. Get a chiller if the water is too warm, a heater if the water is colder, bubblers, plans, recyclers, and other required things that offer a peaceful environment to your new fish.

But do you know what is even more important than these? 

It is a beneficial bacteria. It is an organism that lives inside the aquarium and eats waste. You can call it a waste management officer. If the aquarium is devoid of this microorganism, fish will perishes suddenly. And you cannot do anything about it. 

Without it, no fish will survive.

How to Prevent it?

When you buy a new aquarium, add beneficial microorganism bacteria to it. When you change the water to 100%, add bacteria to maintain the smoothness and ideal conditions for fish. It cycles your aquarium for best usage.

Conclusion

Now you know about the causes by which fish keep dying. You have got your answer. There is not a single reason why your fish perishes suddenly. With these causes and their identification, follow precautionary methods to give your pet fish a happy life. 

You might like our previous article on temperature guides for your fish.

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