Clove Oil for Euthanizing Fish – How to Use It?

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Nobody wants to euthanize their fish, but sometimes, you can’t avoid it. Fish can get sick, get infections, get old, or experience incurable health problems that demand a radical solution. Euthanasia is as radical as they come.

You have several methods of euthanizing your fish, but they’re not all equal. Some are more humane than others, as they don’t inflict the same amount of suffering.

The goal is to do it quickly and painlessly to minimize your fish’s pain and distress during the procedure.

The clove oil method is one of the most popular humane methods of euthanasia, but is it reliable? Let’s see how it works.

Is Clove Oil Good for Euthanizing Pet Fish?

Yes, clove oil is quite effective at euthanizing fish. This oil comes from the Syzygium aromaticum tree, also known as the clove tree. The oil itself is extracted from the tree’s dried-out flower buds and has a variety of applications.

It’s mostly used as a sedative for veterinary use but can also help as:

  • An antimicrobial, killing off a variety of dangerous microorganisms
  • Aids to respiratory problems like asthma and chronic coughing
  • Relieves toothache and muscle pain, etc.

In essence, clove oil acts as a sedative and a sterilizing solution for the most part. Naturally, more research is necessary to determine the substance’s full range of effects since some of its benefits are the result of anecdotal reports.

Clove oil is great for euthanizing fish because it is toxic to them and acts as a powerful sedative. So, it will knock fish unconscious before killing them, minimizing their pain and distress during the process.

How to Humanely Euthanize Your Fish with Clove Oil?

The procedure itself consists of several distinct steps:

  • Prepare the clove oil solution – You first move the fish you aim to euthanize into a separate container. Then you mix the clove oil with some warm water to dilute it a bit before adding it to the kill tank. That’s to prevent the fish from getting overly excited, which can happen when adding concentrated clove oil to their environment. The amount to use is around 0.4 mg per liter of water.
  • Pour and mix – Mix the clove oil solution gently into the fish tank. The goal is to disperse the solution throughout the entire tank uniformly so that all fish get a similar dose. You should see your fish displaying erratic swimming and turn sideways or upside down fairly soon.
  • Wait – The clove oil will render the fish unconscious within seconds, depending on the concentration and how large the fish are. It may even take 1-2 minutes, depending on each case. However, don’t be fooled by the fish’s lack of motion. Clove oil sedates and renders fish immobile, causing them to stop breathing and eventually die of hypoxia. But this doesn’t happen within 1-2 minutes. It will likely take close to 10 minutes for the fish to die completely.
  • Double tap – Once the 10 minutes have passed, you can place your fish in a freezer just for good measure. The extreme cold will finish what the clove oil has started. Remember, fish are extremely resilient animals, and it’s not uncommon to see them raising from the dead long after they’ve been presumed deceased. Don’t worry, they won’t feel a thing. The clove oil in the system will keep them unconscious even after removing them from the water.

The clove oil method is fairly fast, painless, and delivers a quick death. I would say it’s the most effective method of euthanizing your fish, provided you use it correctly. In this sense, the solution’s concentration makes all the difference.

Use an insufficient amount, and you won’t get the desired effect. Use too much, and your fish might experience a shock in the process.

Can You Use Clove Oil to Euthanize Large Fish?

Yes, clove oil works for all fish, no matter their size. It’s the water concentration that makes the difference here, not the fish’s size.

That’s because all fish, regardless of size or species, function the same at a physiological level. They all need to breathe, for one.

So, stick to a concentration of 0.4 mg per liter of water, and this should be enough to kill pretty much any aquarium fish. If you think that the solution takes too much time to deliver its effects, add a few more drops and stir the water again.

The fish may be more resilient in that case.

Where Can You Buy Clove Oil?

Fortunately, clove oil is readily available for sale pretty much everywhere, including Amazon, Walmart, and all other major marketplaces.

Both online and brick-and-stone ones. That’s because clove oil has multiple uses, so people buy it for many reasons.

Clove Oil Alternatives for Euthanizing Fish

So, what to do if there’s no clove oil available? Or if you simply choose not to use it? Fortunately, there are other ways to euthanize your fish humanely, so long as you have the stomach for it.

Here are some effective euthanasia methods to consider:

Stun and Stab

This method is as gruesome as it sounds, but it’s painless and effective. And that’s what you’re actually looking for. The method itself is quite simple.

First, you remove the fish from the tank and place it onto a cloth or aluminum foil. Wrap it tight, then use a blunt object to smash the fish in the head.

Precision is key here, as you don’t want to keep smacking the fish because you can’t aim properly. This is where the wrapping part comes in, as it allows you to pin the slippery fish down without fearing it might get away.

The smacking will disable the fish’s nervous system, rendering it unconscious and destroying the nerves. So, the fish won’t fill anything.

However, the blow may not kill it necessary. To finish the job, you must then use a knife to cut into the fish’s head and destroy the brain.

Insert the blade right behind the eyes, where the brain is located. This will kill the unconscious fish immediately.


Clove oil isn’t the only substance used to euthanize fish humanely. MS222 is another good product in this sense. This is Tricaine Methanesulfonate which explains why the MS222 name is so popular.

Benzocaine Hydrochloride is another good option in this sense. These are anesthetics, so they ensure a quick and painless death, provided you use them properly.

You should speak to your fish vet before using them, as the label instructions may not meet your exact needs.

Professional Euthanasia

I understand why some people avoid euthanizing their fish themselves altogether. The stun-and-stab method is humane for the fish, but it’s hard on the person who applies it. You can’t escape the gore, unfortunately.

Using clove oil or other drugs is a game of precision. If you don’t use the right concentrations, the fish may suffer in the process.

So, some people go to the vet to avoid all these issues. The veterinarian will most likely use injections to euthanize the fish.

Sodium phenobarbital is used in this case and the vet will inject it into the fish’s bloodstream. Death will come fast as the fish is rendered unconscious soon.

It’s painless and quick.

But are there other methods of euthanizing your fish that I haven’t mentioned? Sure, there are. The problem is that those don’t qualify as humane. Many people use many methods to dispose of their sick or dying fish, but not all of them are humane.

Here’s what I mean by that:

  • Freezing the fish – It’s as easy as it sounds. You either throw the fish in ice-cold water or simply place it in the freezer as it is. Sure, the fish will eventually die, but the shock and suffering that it will experience along the way will be severe.
  • Boiling the fish – This goes to the other extreme and is just as deadly and painful. The boiling water will cause extensive damage that will kill the fish. But it’s extremely painful in the process.
  • Flushing down the toilet – This is probably the most widespread method of euthanizing aquarium fish for some reason. I suspect that people default to this one mostly due to the lack of personal involvement that the method comes with. You just flush the water, and the fish is gone. No gore, no witnessing any suffering or pain, etc. The problem is that the fish gets to suffer tremendously along the way. Not to mention, its dead body can pollute the environment since aquarium fish contain parasites and bacteria that can infect other animals.
  • Feeding the fish to pets – This is probably the worst thing you can do. Fish contain a variety of parasites which can infect and even kill your pet. Don’t feed them the dying fish, neither dead nor alive.
  • Dousing the fish in alcohol – Yes, some people use alcohol, mostly vodka, to kill their fish. Granted, this is quite an effective killing method because the concentrated alcohol will burn the fish’s gills, delivering a swift death. But it’s also extremely painful, so I wouldn’t recommend it.
  • Suffocate the fish – This comes down to simply removing the fish from the water and allowing hypoxia to take place. The fish will eventually suffocate and die, but the process will take a long time, and the animal will suffer greatly during the process.
  • CO2 poisoningInjecting CO2 into the fish’s environment will eventually kill the animal. CO2 is toxic and will cause the fish to suffocate since CO2 displaces water oxygen. The problem is that the fish isn’t rendered unconscious immediately. It will first struggle to breathe for a while, so it will suffer significantly along the way.

As you can tell, I don’t recommend any of these euthanasia methods as they’re simply dangerous for the environment, too gruesome, and overly distressing to your fish. In other words, they violate the humane policy we’re after.

Some people try to circumvent the entire euthanasia aspect altogether and release the sick or dying fish into the wild. Let them live their last moments of their lives free, and in peace, they say.

The problem is that, by doing so, these people are oblivious to the consequences of their actions. Releasing fish into the wild is the worst thing you can do. It doesn’t matter whether they’re dying or are sick, or perfectly healthy.

Dying and sick fish will infect the water with parasites and bacteria, killing other fish in the process. Your sick fish may even recover when released into the wild, which will create different problems along the way.

Goldfish, for instance, are considered pests due to their high appetite and reproductive prowess.

You’re forbidden from releasing them into the wild since they can destroy entire fish populations and take over entire ecosystems.

Never release aquarium fish into the wild, however tempting that might be.


While you may not want to euthanize your fish, you may sometimes need to do it.

If you’re ready for the task yourself, consider one of the more humane alternatives I’ve mentioned. If not, contact your vet to assist in the process.

Author Image Fabian
I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.
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