Euthanize fish

How Do You Euthanize a Fish?

Fish keeping is a wonderful and exiting hobby. However, just like every other pet, your fish will pass away at some point. This is the worst part of keeping any pet and is the saddest. However, when it comes to fish, there aren’t experienced vets around most of the time, and if your fish becomes terminally ill, you may need to consider euthanizing your pet.

Fish medicine is not at the level that human medicine is, so if your fish ends up with kidney failure or cancer, euthanization may be the kindest option. Fish surgery is possible, but it is rare to find someone willing to do it. There are several methods available to euthanize your fish, but some require a stronger stomach than others. Some simply let your fish fall asleep while others are fast but look gruesome.

We will cover clove oil, clove oil and vodka, freezing, pithing, hammer method, methods to avoid, and how to dispose of the body.

Clove Oil

Clove oil is commonly used to treat tooth aches and is found in most grocery and drug stores. In humans, it acts as a local anesthetic, but for fish, it can act as a general anesthetic. Anesthesia either numbs a specific area or causes someone to fall unconscious.

Clove oil can be used to keep fish asleep during cosmetic surgery at home and is also a euthanization method. The key is to first put the fish to sleep so that they can’t feel anything. After that, you must use a large amount of clove oil into the water to kill the fish.

You will need a larger dose for larger fish, but for bettas, you will only need a few drops. Get a small container, less than one liter, and a small medicine container. After that, fill both containers with warm tank water and move your fish to the small container. In the small medicine container, add four drops of clove oil and shake vigorously.

Over a period of 5 to 10 minutes, slowly add the clove oil solution. First, your fish will pass out, but the gills will still be moving. Continue to add the solution until the gill movement stops. After ten to twenty minutes of no gill movement, your fish is deceased.

Clove Oil and Vodka

This method is almost identical to the clove oil method. However, the difference is the speed of death after the fish is unconscious. The fish should still be in a separate container of tank water with the clove oil mixture slowly dropped in. 

The difference arises in what happens after the fish is unconscious. At this point, you should add a good dose of vodka to the water. Do not do this while the fish is awake, as it will be very painful. You must be able to tell when your fish is unconscious, otherwise you should just use the clove oil method.

The vodka will quickly stop your fish’s gill movement and cause death. Some prefer this method to the clove oil method because it allows them to have a final drink with their pet. A last moment of solidarity.


This method uses the fish’s cold-blooded body against them. To clarify, the surrounding water temperature controls a fish’s metabolism. Therefore, the higher the temperature, the faster the metabolism. The slower the temperature, the slower their metabolism.

Metabolism affects every organ in a betta’s body, including the brain and circulatory system. In other words, this means slowing down the body temperature will cause your fish to fall asleep, and if the temperature continues to drop, the fish won’t wake up.

Firstly, prepare a bucket full of ice water and make sure it is extremely cold. Secondly, take out your fish and place it in a container of its warm tank water. After that, place your fish’s container in the bucket of ice water, but don’t allow the ice water to get in. Your fish will not like this and may act upset, but it will soon slow down and pass away.

You could also place the container in the freezer, but it can take longer that way. Some also place the fish directly into the ice water, but this will result in shock and potentially a good deal of stress. The clove oil method is the most humane, but this is a good alternative.


Pithing is the act of destroying the brain, often with a sharp needle. In other words, the needle pierces the skull and is quickly twirled around to destroy the brain and the senses. Brains have no nerve endings, so the only pain associated with this method is the entry site in the skin.

However, this method is not for the faint hearted and should only be done by those experienced with it. For instance, if you miss the brain or the needle isn’t twirled properly, the fish will experience too much pain for it to be considered humane. However, it is a very fast and humane method when done properly, often more humane than clove oil.

Decapitation is another quick and easy method and involves pithing as well. Once you sever the head, you will want to pith the brain to avoid the fish feeling any extended pain. Any method that destroys the brain is fast, effective, and humane.


The hammer method is the most gruesome and not for the faint of heart. However, it is a very humane and fast method. It does need to be carried out as fast as possible. You will need a hammer, a bag, and your fish.

Firstly, place your fish inside of the bag as quickly as possible. Do not add any water to the bag. Take a hammer and hit the head of the fish to destroy the brain. You can then dispose of the body.

Methods to Avoid

Some classic methods are extremely inhumane. Some flush live, but sick, fish down the toilet and others pull them out of the water. Because these methods cause severe pain and stress to the fish, they are not considered humane.

Flushing live fish is an extremely bad practice. For example, not only do you risk infecting local native fish with whatever your fish caught, but it is a slow and painful death. The toilet water is full of chlorine, which burns your fish’s external and internal body as it breathes.

The tumbling down a drain will also cause severe stress and damage to your fish. While the chlorine burns away at its vital organs, the current smashes your betta into the walls of pipes. In addition, this torture can continue for hours depending on the chlorine concentration of your water and whether your fish sustained serious internal damage from bouncing around the pipes.

Leaving a fish out of water will definitely kill it, but it isn’t a fast death. The fish dies once the gills are too dry to function, but the fins, scales, and eyes will dry first. Additionally, this method of death can take over three or four hours to kill the fish depending on the species.

For example, betta fish have a labyrinth organ that allows them to breathe atmospheric air. This means they will stay alive for over an hour after the gill dries up. This is good in the sense that you may be able to save a fish that jumped over an hour ago, but it’s an awful method to kill a fish.

Body Disposal

When disposing of a fish’s body, the worst thing you can do is flush the body. By allowing the disease, parasite, or other illness that affected your fish to enter local water ways, you put other fish at risk. It is possible for the illness to affect local sources of water and fish and devastate local ecosystems.

The best method of disposal, while some may consider it disrespectful, is throwing the body away. It will not be able to affect local fish populations and since your pet has passed, he or she will not mind where their body ends up.

If you do not have rivers, lakes, streams, or other bodies of water near your home, you can bury your pet. Have some kind of grave marker on hand and give your fish a nice burial. That way you will be able to visit them again if you feel the need.

In conclusion, there are many humane methods to euthanize your fish if it comes down to it. You should only use these as a last resort if your fish has a terminal disease. In addition, you must also dispose of the body properly to avoid other people losing their fish.

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