Euthanasia: A Humane End for a Life in Suffering

One of the most difficult decisions any pet owner must make is whether or not to put a beloved animal companion out of its suffering when faced with prolonged disease and failing treatment. The heart-wrenching, serious, consideration for euthanasia is not easy but sometimes necessary out of compassion for our animals. Unlike options for larger animals when it comes to euthanasia, or the humane taking of life to end suffering, Betta fish owners must often be the ones to put their treasured aquatic companions out of misery. While many betta lovers choose to try and fight illness to the end, some are faced with an impossible situation and choose to take matters into their own hands but receive conflicting information about which is most humane to end a precious creature’s life.

There are many ways to end a betta’s suffering but doing so requires serious though, compassion, and responsibility. Euthanasia should never be an option for those who no longer want their fish, for those whose living situations or financial situations make it undesirable to have a pet, or for those who simply find it easier to end a fish’s life rather than care for it. Like with a dog, cat, rodent, or lizard, Betta fish are living things that deserve full dedications in times of need and not just when convenient. The following content should be considered only in the most extreme situations when no other options are available. To find treatments for most Betta fish diseases, please take a look at this article so you can consider your options. If you feel that you must consider euthanasia for humane purposes, please read on.

A betta suffering from dropsy may have no cure but lots of suffering, leading to an owner considering euthanasia. Photo by

A betta suffering from dropsy may have no cure but lots of suffering, leading to an owner considering euthanasia. Photo by

While the internet can be full of helpful advice from well-meaning individuals who have experience dealing with specific situations, it is important to recognize that it is also full of misinformation and advice from people who may or may not have had the right experience when dealing with specific situations. Euthanasia is not a situation most people treat lightly or are willing to risk accidents with so it is important to consider information from scientific or specialized sources. It is also worth noting that while fish generally tend to respond to similar techniques in care and treatments, there are individual species and types that may not react the same to identical approaches. Betta fish need to be considered as Betta fish, not just fish, when considering a topic as serious as euthanasia in order ensure a painless or near painless passing. For these reasons, all the following information is sourced from reliable resources such as the RSPCA Australia, the American Veterinary Medical Association, and Practical Fish Keeping Magazine, and the original articles are cited and linked at the bottom for further reading and research.

Humane Methods

It is often debated as to which method is the most humane and least painful. Unfortunately, the level of humanity often depends on the experience level and skill of completing the task in certain approaches to euthanasia. Should these methods be attempted by an unskilled or nervous pet owner the results may be the complete opposite of your painless death attempt. The most commonly identified humane euthanasia method is one that most people have a hard time stomaching—decapitation. It is sometimes paired with stunning and pithing as the least painful way for your fish to go, though arguable not the least painful for you as the owner. The description of these methods make some people uneasy, uncomfortable, and disturbed, so please skip to the next section if you feel you may become affected by the nature of this content.

Decapitation, Stunning, Blunt Trauma, and Pithing

First there is decapitation, or the slicing off of the animal’s head. Gruesome to most, this physical method of euthanasia. For starters, decapitation and pithing (the destruction of the brain) must be done together. Decapitation without pithing can result in the separated head being very much alive, aware, and in considerable amounts of pain minutes after decapitation. After a clean, precise, pithing requires a sharp object to be injected into the brain cavity in a very specific way. Inexperienced owner will want to seek advice from those experienced in this method of euthanasia. Incorrect decapitation and pithing can result in severe pain and suffering, potentially that even worse than the disease you may be trying to save your fish from, and should be completely avoided if you are not fully confident in your ability to carry out the act. Nervousness can affect the precision of your actions and should be avoided when attempting this method as well.

Some aquarists also recommend stunning, inducing comas, or blunt trauma as way to humane euthanize a fish and may even suggest knocking a fish out before decapitation and euthanasia. These methods will not work on Betta fish easily, if at all, and run high risk. Too strong a blow to your fish’s head and the results will be neither pretty nor kind. Too weak a blow and you will not get the results you are seeking and your fish may very well regain consciousness during its regretful demise. Blunt trauma is usually reserved for much larger fish and should be avoided completely for Betta fish species, which are quite small.

Clove Oil

Pure clove oil can be used for humane euthanasia. Photo by Now Foods

This method is usually the first Betta fish owners turn to when deciding euthanasia is right for their situations. It is often regarded as the kindest method with the least amount of pain and suffering for both fish and owner. Close oil contains eugenol and is a sedative for fish. At high doses it can be used to slowly and painlessly euthanize small fish species, such as Betta fish. Unlike many sedatives, close oil is readily available to most people through pharmacies and chemists. Some fish medications, such as Aqua-Sed, contain this as an active ingredient as well and it can be obtained at local fish stores. It is important to strictly follow guidelines when using this method to euthanize a fish because there is always a risk of suffering with antibiotics if instructions are not followed.

400mg of clove oil per liter of water is needed to euthanize fish exposed to it. Before adding it to your tank, mix the clove oil with warm water in order to dissolve the close oil into it. Avoid chunks of the oil remaining present and make sure the mixture is thoroughly diluted. Adding too much too soon can overexcite and cause harm to your fish, so be sure to add the mixture slowly. It should be introduced slowly to the tank over the course of five minutes to harmlessly put your fish to sleep. Fish that are exposed to clove oil begin to lose consciousness, stop breathing, and die from a lack of oxygen. The mixture of the clove oil and water must be appropriate and the fish must sit in it for at least 10 minutes for it to be effective and humane.

This method is strictly different from suffocation, an often suggested and painful method to dispose of a fish’s life, because the fish first goes to sleep and is unaware of its slow removal of life. It is considered to be painless or containing very little pain.


This is different to freezing and is often confused with freezing. Freezing falls into the inhumane category and should be avoided all together. Chilling, if used appropriately and accurately, can be a humane method but is certainly not the most effective in painlessness. It is not ever okay to take a fish and let it sit in a freezer, for example, even if the water slowly freezes, and it is not okay to place a fish onto some ice in an attempt to shock it. With care, it is possible to chill a fish into unconsciousness and into death without severe stress.

Placing a fish in a freezer is far different from chilling it as a form of euthanasia; freezing is inhumane. Photo by

The key to chilling is making sure that ice does not touch the body in order to avoid ice crystals from forming, according to Dr. Lynne Sneddon of the Institute of Integrative Biology and the work of Monte Matthews and Zoltan Varga. If done incorrectly, ice crystals can form inside the body and cause pain before the loss of consciousness. If done correctly, “gill movements cease after 10 seconds so it’s quick and it’s less aversive than anaesthesia.”

The key to a successful euthanasia by chilling is correct temperature. One method is exposing a fish to ice water in its water until the water slowly lowers the temperature enough to make a fish lose consciousness followed by maceration, which is the softening of a solid through soaking. Maceration for fish requires specialist equipment and should not be attempted without access to it.

It is important to note, however, that there is a debate in the humanity of chilling. There are some who suspect that chilling may reduce nerve feeling but not eliminate it. This means that some scientists fear that while movement may stop from numbing and the fish can no longer move from the cold, it may still be able to full certain amounts of pain. This is something to consider seriously before considering this method.

Inhumane Methods to Avoid

Now it is time to discuss the worst methods, the methods to never ever attempt, in euthanizing your fish. Not only are the following methods unfounded and based in unscientific connections, they are cruel and painful to the fish they are enacted upon. Check this list before considering a method because if it lands on here you know it is certainly a method to avoid.


This is the big one. This is the one many people associate with dead fish: flushing it down the toilet. Dead or alive, this is not something that should be done for fish. Aside from dead with being far more solid than what should end up in a sewer system and creating blockages, fish do not belong down the toilet as a way to dispose them. Even if the damage to the sewer systems is not a concern of yours, flushing a sick fish is one of the most inhumane methods of euthanasia and may even be illegal in some parts of the world.

Flushing is one of the worst ways to end a fish’s life. Photo by

Fish do not necessarily die when flushed. Cold and warm water quickly mix, causing immediate stress, and the uncomfortable push down the pipes is not the end of it. Fish can survive the push past the u-bend and slowly die from suffocation in human excrement. This is not ideal for any living creature. A horrible, disgusting, way to go is even less favorable than dying from disease.

CO2 Exposure

This method is more commonly recommended in the United States than in other parts of the world. An outdated method that brings more pain than peace, the idea is that by exposing a fish to carbon dioxide by adding Alka-Seltzer to the water it will die similarly to those under a sedative. This idea is rooted in 1980s research that cite Alka-Seltzer as a fish sedative. In 30 years’ time it is not surprising that new research has found more humane methods and poked holes in the idea of humanity for this approach. First, Alka-Seltzer is known to create discomfort for fish exposed to it. Second, it is acidic and can burn the fish exposed to it in a slow and painful death.

Betta fish, which are particularly sensitive to acidic water and need water as close to neutral as possible, would have particularly negative reactions considering the effects. But it is not just Betta fish that this would be a cruel method for euthanasia for. The use of CO2 exposure has been banned in European fish farms due to the method being legally identified as cruel and painful. While it may have been thought of as the best in the 1980s, science has advanced and it is time to move forward from such approaches to ending a fish’s life.


By no means should any form of boiling be considered as a humane end for a suffering animal. While not a common suggestion, boiling does pop up from time to time. There is no scientific research or evidence that boiling a fish is even remotely humane. This includes microwaving a fish, adding boiling water to a tank, or even dropping a suffering fish into boiling water in an attempt to shock it. By all means, this is completely out of the question and absolute animal abuse if attempted.


Euthanasia is a serious responsibility that befalls many a pet owner. It is not lighthearted. It is not without emotion. It is not without fears and regret. Betta fish owners, who often face the most conflicting information even for basic care, tend to have it particularly hard when considering the kindest ways to send their companions under the rainbow bridge. I hope that nobody who reads this blog ever has to consider this as an option but, even more so, I hope that those who do, do so with the greatest regard and consideration for their suffering pets and research the method best for them. For now it appears that clove oil is the easiest and kindest method for most fish lovers and it may pay to have a bottle on hand in the case of emergency, so that a panicked owner will not rush to try a backup plan in an extreme case that may do more harm than good. It is rare that euthanasia is required and even rarer that it is the only option left. I hope that nobody who has a place in their heart for animals ever has to face this decision.



” AVMA Guidelines for the Euthanasia of Animals.” AVMA Guidelines for the Euthanasia of Animals. American Vetinary Medical Association, 2013. Web. 28 Mar. 2015. .

Hill, Nathan. “Painful Fish Deaths? You Might Be Guilty…” Weblog post. Practical Fish Keeping Magazine. Practical Fish Keeping Magazine, 26 Apr. 2013. Web. 28 Mar. 2015. .

Kayne, R. “What Is the Most Humane Way to Euthanize a Fish?” WiseGEEK. WiseGEEK, 12 Mar. 2015. Web. 28 Mar. 2015. .

“RSPCA Australia Knowledgebase.” What Is the Most Humane Way to Euthanase Aquarium Fish? -. RSPCA Australia Knowledgebase, 11 Mar. 2015. Web. 28 Mar. 2015. .