How to Euthanize a Fish: Humane and Sensitive Methods

Charlie Morton

Charlie Morton


how to euthanize a fish

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We know how hard it can be to say goodbye to a beloved pet fish, but in instances when there’s no chance of recovery, euthanasia can sometimes be the kindest option.

We’ve consulted top animal welfare bodies such as the RSPCA for the most up-to-date opinions on this sensitive topic.

Here, we’ll walk you through the most humane methods currently available.

Key Takeaways

  • Euthanasia should only be regarded as the last option when your fish is sick or injured beyond hope of recovery. A new home can always be found for healthy unwanted fish.
  • Veterinary euthanasia and the clove oil method are the two most humane and preferred methods available to most fish keepers. Avoid misguided methods that are cruel and ineffective.
  • Dispose of a deceased fish by burial, cremation, or via safe garbage disposal. Never flush a live or dead fish down the toilet!

Do I Need to Euthanize My Fish?

We must emphasize that euthanasia is an option if and only if recovery is not possible.

A healthy fish should be every fish keeper’s top priority. Even serious diseases and health issues are often treatable.

But if your fish is sick or injured beyond hope of recovery, it’s often kinder to end its life quickly and humanely than to continue allowing it to suffer.

Getting Rid of an Unwanted Fish

There may be other reasons to consider getting rid of a pet fish that don’t include sickness or injury. Getting a new fish that may be more aggressive, moving, or other big life events may have you changing your mind about owning a fish.

In any of these cases, you must know your options.

Pet Stores– Pet stores are often a great starting point when you want to get rid of a pet fish. Depending on the type of fish you have and its age and condition, you may even make a bit of money!

Donate- Donating a fish to a doctor’s office or school is another great way to get rid of a fish. While you’re less likely to make money this way, it may be tax deductible, and you’ll feel great about donating to a good cause!

Reach Out to Friends/Family- Because fish are so low maintenance compared to other pets, it’s very possible that you know someone who’ll be willing to take in your pet on a temporary or permanent basis.

What To Do Before Euthanasia

You may still be wondering if there is anything else you can do to make your fish’s life just a little bit better. And the good news is there is!

You can provide comfort to your fish by following a few simple guidelines:

Improve Water Quality and Parameters

Excellent water quality is important for your fish throughout its entire life, not just the end. However, dying fish are extra sensitive to most things, so be sure to test your aquarium water quality and clean it as necessary. (Be sure you know what pH your pet requires).

Remove From Tank

This is as much for the comfort of your dying fish as it is for the safety of any other fish you may own. Not only do dying fish prefer to be secluded, but they might also carry parasites or diseases that can endanger other fish.

Increase Water Temperature

A slight increase in your fish’s water temperature may also be comforting. This compensates for the lack of heat they are putting off by swimming and playing energetically.

Be Quiet

Have you ever seen a “Do Not Touch Glass” sign at a pet store and wondered why? That’s because fish can become stressed out through vibrations that are carried through sound that humans are not aware of. One of the easiest things you can do to comfort a fish is to provide them with a peaceful and quiet environment.

Watch Their Diet

Be careful not to overfeed a dying fish. This can cause discomfort from being bloated if the fish eats everything you feed it, or it could cause the food to go uneaten and create dirty water.

Humane Methods of Euthanizing a Fish

If you’ve concluded that euthanasia is the best option for your pet, we have a few different recommendations for humane methods. We’ll discuss the pros and cons of each.

The Veterinarian Method

A veterinarian method is a great option for those who don’t want to put their pet down personally. The veterinarian method ensures that your fish will have a painless death via an overdose of an anesthetic injection.

However, the cons of this method are also something to consider. A typical amount that a veterinary clinic would charge for fish euthanasia services ranges from $50- $150.

The Clove Oil Method

Clove oil is a great method for euthanizing fish. It is highly recommended for its peaceful nature, as the clove oil acts as a sedative and puts the fish to sleep.

Although it cannot yet be proven, likely, your pet will not feel much (or perhaps any) pain. This method is also extremely cost-friendly as clove oil is commonly found at grocery stores for less than $10.

To use this method, you will need to follow only a few simple steps:

  • Transfer your fish to a smaller container such as an ice cream tub with water from the aquarium.
  • Mix tank water and several drops of clove oil in another small container. Then stir the mixture. (Do not add clove oil directly to fish water).
  • Add the mixture to your fish’s water and wait a few minutes for them to fall asleep.
  • Once your fish has fallen asleep, you should add a few more drops of clove oil to complete the process. Note that additional drops may be required for larger fish.
  • If after half an hour has passed, you are still seeing movement, just add a few more drops accordingly.
  • After the gills have stopped moving, leave the fish for a further hour or more to ensure death is complete.

Methods To Avoid

There are many myths circulating about supposedly humane methods of putting down a pet fish that are very cruel. It should be obvious that methods such as decapitation and ice baths are barbaric, but there are others that we need to debunk more thoroughly:

Flushing Down the Toilet

Flushing a fish down the toilet is an extremely inhumane method of euthanasia. This is an example of the “out of sight, out of mind” mentality.

Flushing a fish down the toilet is not a guaranteed way to kill them quickly. Likely what will happen is that your fish will be violently transported through the pipes and drainage systems only to die in a sewage dump.

The Baking Soda Method

Baking soda or bicarbonate of soda should never be used to euthanize a fish as it’s likely extremely painful for them. If you’ve ever placed baking soda on a wound or sore gum, you’ll know how painful it could be for a fish’s sensitive gills.

Blunt Force

Blunt force, also sometimes referred to as stunning, is another inhumane way some people have tried to euthanize their pet fish.

This method typically delivers a precise blow to a fish’s skull between its eyes. More often than not, this method is used by fishermen. After fishing in my youth, I know that this method is not always quick or easy.

There is little room for error as it goes without saying how cruel it would be to beat a fish without killing it.

The Vodka Method

Using the vodka method, the fish suffers alcohol poisoning until it dies. One of the most controversial methods, it can’t be proven whether the fish will experience unnecessary pain.

In my opinion, however, it is likely very painful. It is not instantaneous and, therefore, not recommended.

The Carbon Dioxide Method

The carbon dioxide method directly introduces carbon dioxide into the fish’s water. It is another of the most inhumane ways to euthanize a fish, as it essentially suffocates the fish to a painful death.

Slow and unpleasant, it’s not dissimilar from taking your fish out of the water and waiting for it to die.

Disposing of a Dead Fish

how to euthanize a fish

Dead fish must always be removed from the water immediately to prevent decomposition and infection in the tank’s water. Whether you choose to euthanize your fish or you find them dead in their tank, disposal must be handled properly.

Outdoor Burial

One of the easiest methods of fish disposal is a burial. This is a great option for convenience and environmental benefits.

All you’ll need is a shovel and some dirt for this method. When burying a fish, dig at least 4 inches deep to avoid your fish becoming food for other animals.

Be sure to bury your fish in a biodegradable container. Doing so will also allow your fish to function as a fertilizer to the soil it’s buried in!

This option is great for closure as you can bury your fish close to home and remember their grave with a flower bush or tree – it will even fertilize your plant and help it grow!

Plant Burial

Similar to the outdoor burial option, a plant burial may be better suited for those who don’t have their own yards or even those who just like plants.

This method involves burying your fish in a large planted pot. As long as you bury your fish a minimum of 4 inches deep, you can avoid any unwanted smells or the spread of germs. Your plant will also be able to use the nutrients from your fish!


Cremation is another great way to keep a piece of your pet with you forever.

If you decide to cremate a fish, you can keep the ashes. This option is safest for a vet or even a pet cremation clinic!

Throw Your Fish Away

This method is a bit more controversial, but when done properly is still a moral way to dispose of a deceased fish.

Throwing your fish away is a better option for those who aren’t as sentimental with their fish. To do this properly, you will need a biodegradable container to secure your fish. This protects the environment and the people who have to sort through your waste!

Why Not To Flush a Dead Fish Down the Toilet

Many believe it’s okay to flush a dead fish down the toilet. However, just as you should not flush a live fish down the toilet, you shouldn’t flush their dead body either.

This could cause many problems as septic systems are not meant to handle fish. Remember that fish tank diseases can easily infect local water sources.


While it’s never an easy decision, we sincerely hope that this guide has helped you know when and how to euthanize your pet fish with kindness and dignity.

If in doubt, consider asking a specialist vet for a second opinion.

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