How to Euthanize a Fish in 2 Humanely Ways

December 6, 2016

There is nothing more heartbreaking than losing your beloved pet, especially if you tried to take care of it. When your fish is sick, you would even try to consult a veterinarian to cure it. However, is euthanasia rightful when your fish is in distress and is dying?

If you know that your fish is in so much pain and is gradually getting weak, you may consider euthanizing it. In this case, you have to realize that euthanasia is the only option left for your fish. A lot of people do not resort to euthanasia.

Some would rather want to see their fish suffer and die in the usual course. You may choose this routine, or you can go with speeding the process for your fish’ sake. You should consider the condition of the fish before deciding on your next actions. So, read on to find out the two primary ways on how to euthanize a fish.


When Should You Consider Euthanasia

Here are some of the factors you need to determine before choosing the fastest way to end the life of your pet:

  • When Your Fish Becomes Too Stressed

Did you know that a fish also considers its biological survival? Fishes need to search for food, consume food, flee from predators, and engage in their natural activities. When a fish can no longer fulfill these things mentioned above, it will stress out. It weakens the fish and slowly dies out.

  • When Your Fish is Sick

Another scenario to consider euthanasia is when your fish becomes ill. When your pet’s illness becomes contagious or untreatable, you have to make its suffering stop. An example of this is when your fish becomes dropsy; your fish goes through the same disease over and over again, and it is not responding to medications. Also, you may consider this as a resort for fishes that are too old and weak. These pets become the primary source of infectious pathogens in your aquarium.

  • Whe n Breeding Your Fish

When you want to breed your pet, especially for fishes with particular characteristics like guppies, discus, and fancy, you may have to euthanize them. You may need to cull the fry which does not seem fitting to reach their natural growth and development.

  • When Your Fish Becomes a Threat to the Ecosystem

Lastly, your fish becomes a candidate for euthanasia if he could infect the ecology. When your fish can contaminate other fishes in the aquarium, the only way out is to end its life.

Methods to Euthanize Your Fish

If your fish falls under the categories above, it is more humane to choose euthanasia than to let it die slowly. Your pet may inevitably feel pain. However, you may minimize the pain and end its life quickly.

Euthanasia has two main categories: the old school method and the gentler method. It is up to you what strategy you shall use to end the life of your pet humanely.

The Old School Methods of Euthanasia

These strategies are the most traditional among pet owners, especially those who do not have time to select other methods. But, these ways are quite outdated, and they are not the best options out there! Here are some methods that fall in this category:

  • Freezing Your Fish

Putting your fish in a frozen water is a common way to euthanize your fish. To freeze your pet, you need to freeze the water in a small bag until you make it mushy. Then, place your fish in the frozen water and try to refreeze it. A lot of people advocate this approach. However, some individuals think that this method may cause discomfort to your fish.

Out of the old school ways, this approach is most likely the most inhumane. In fact, some animal rights groups criticize freezing fish as a way of euthanizing fishes. The only way they would accept this method of cooling is when the animal is already euthanized before freezing it.

  • Decapitating Your Fish Quickly and Surely

As what it apparently means, decapitation is a method that involves getting the fish out of the water. Then, you have to obtain a knife to slice off its head. By doing so, you do not prolong its agony. However, an issue with this approach is that the pet may still feel something when you try to chop it. It may also bring about temporary pain.

But, what’s better here is that the method is quick. All you have to consider is to do the task swiftly and steadily. And once you start the process, do not hesitate and continue it. A lot of pet lovers agree with this method as long as it goes with anesthesia.

  • Adding More Carbon Dioxide in the Water

Carbon dioxide typically fills the water your fish lives in because of the process of respiration. Consequently, you can also use this approach to stop the suffering of your fish. What you need to do is to add more carbon dioxide to the water and lower down the oxygen content of the environment. It will suffocate your fish.

Alka-Seltzer is a well-known source of carbon dioxide that you can release into the water. Such method may be inoffensive enough. But, for most people, it is still quite disturbing to see their fish moving around and gasping for oxygen. Thus, to make sure of its death, you may try to decapitate or freeze your fish.

A lot of vets and pet lovers allow this method. Veterinarians suggest at least eight tablets of Alka Seltzer for each gallon of water for this process to be successful.

  • Cracking the Neck of Your Fish

Some individuals are brave enough to break the neck of their fish. Fish die instantly by hitting it with something hard or cracking its neck using the kitchen counter. But, before you proceed with the method, you need to put the fish in a plastic bag.

A lot of people say that decapitation is a more efficient way to break the neck of the fish. That’s why they will choose to chop the fish over snapping the neck of your fish.

Milder Ways to End the Life of Your Fish

Average pet owners usually use the methods above to euthanize their fishes. However, there is another way to be gentler and more humane to your pet. A lot of these ways are more typical in the vet’s clinic than at home.

  • Euthanasia by Overdosing Your Pet With Anesthetics

Here are some of the anesthesia you can use to stop the suffering of your fish:

Tricaine Methanesulfonate or TMS

It is a method that is most probably used by people with a few experience when it comes to euthanizing a fish in a humane manner. In fact, universities commonly use this method when using animals for experiments. You can also call TMS as MS222. Vets also refer to this drug as Finquel. MS222 is an FDA accepted anesthesia for euthanasia. Moreover, it is the only FDA-approved substance when it comes to ending the life of your fish.

  • Clove Oil or Vodka

A lot of fish owners advocate using vodka or clove oil to anesthetize their fishes. You can anesthetize your fish first utilizing the clove oil. Then, you can euthanize your fish using another method. But, to directly kill your fish with clove oil, you may give a stronger concentration to your fish.

  • Benzocaine Hydrochloride

It is a type of medication that needs your veterinarian’s prescription. Thus, you cannot purchase it over the counter to kill your fish. A lot of pet lovers advocate the use of Benzocaine.

However, not the straight utilization of the drug. You see, you have to combine the medication with ethanol or acetone to blend it in the water. Such medication can cause irritations to your fish’s tissues, and it will eventually cause its death.

  • Death by Injecting Barbiturates

Another way to kill your fish is by administering barbiturates into the fish’s bloodstream. It is a humane approach because you need to make the fish unconscious first before euthanizing it. However, you will somewhat find this method quite difficult to execute, especially that you still need the vet’s prescription.

But, with the help of your veterinarian, you can use this method. Vets typically utilize this approach all the time for pets that needs euthanasia.


Euthanasia may be one of the hardest tasks to fulfill, especially for pet lovers. Moreover, choosing a method to euthanize your fish may also be difficult. However, when you know that your fish is already suffering, you know that it is the best thing to do.

To help you make a decision to end the life of your pet, you have to determine if your pet will make it or not. If your fish suffers from a severe disease or is not responding to treatment, euthanasia may be the ideal option.

It may seem harsh to allow the death of your fish, but if it is in pain, then it is the kindest thing you can do. If you decide to go for euthanasia, you need to make sure that you follow the methods listed above. By doing so, you will not end up causing more discomfort and pain to your fish.

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About the Author


Hello, fishing world! My name is Bella. Yes, you got me right, I am a woman! But, I am a woman not only fond of cooking and shopping. I am a woman who shows interest in everything that covers topics regarding fishing. Don’t get me wrong! I believe that the world of fishing is not exclusively for men! In fact, I, myself enjoy fishing. That’s why I created this website.

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