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Aqualife Beauty Uncategorized How to humanely put down a fish; euthanize your pet fish quickly and humanely:

How to humanely put down a fish; euthanize your pet fish quickly and humanely:

How to humanely put down a fish is probably the last thing in your mind. However, has it ever occurred to you that you’ll one day say final goodbyes to your pet fish? And has it also occurred to you that you’re most likely the one to put down the fish?

Well, let me tell you this, someday, hopefully not soon you will. Making the euthanasia decision is obviously very heart wrenching. However, at the face of a severe illness unresponsive to any treatment, it probably is the only way out.

How to euthanize a pet fish

Therefore before then, besides courage, I trust you’ll have the skill on how to humanely put down a fish. It’s the least it deserves.

Having said that, this guide will help you know in advance how to put down a fish peacefully. Well, when it’s the only option left. The parting shouldn’t be painful for your departed friend. Just know what to do when your fish is dying.

When may you need to learn how to humanely put down a fish?

Despite the joys and loads of stress relief pet fish brings you, be ready for that unpleasant call on you. I can’t promise it won’t be heartbreaking.

Well, while the aquarium is the only place your fish will call home in your house, it can also be its death trap.

Toxic and lethal compounds may inhabit the tank if the conditions are not optimal. These eventually are sources of illnesses which may afflict your pet to its sunset days. Some of these are severe ammonia poisoning.

To the contrary, the tank conditions may still be optimal must your fish may still be staring death. This could be say from injuries that are not healing as fast.

You may be asking, how can fish be injured in the tank? Well, injuries may be bruises caused for instance by sharp gravel and/or driftwoods. These particularly will be common with bottom tank dwellers and substrate scavengers.  

Moreover, they could also be from attack bites and fights from and with tankmates. Such injuries may be septic thus leaving your fish dying slowly in the aquarium.

As a result therefore, if no treatment is working to alleviate the pain, then this could well be when to euthanize the fish.  

At this point, the big worry is whether you know how to humanely put down a fish.

Further, most people who unfortunately don’t know what to do with unwanted fish consider killing as the first option. Ideally, that’s not a good reason to euthanize a pet fish. Don’t be one of them.

There are many keepers who would take in that fish; or better yet, take it to pet stores. There, they can easily get new homely friends. However, if you must, then mercy killing is how to do it.

You may also consider euthanizing fish when you want to cull fish in your aquarium.

In addition, it’s also unavoidable when you want to manage outbreaks in the tank. Remove the sick fish especially if a disease spreads easily.

Finally, you may be forced to do fish mercy killing for poor genes elimination. Such are prevalent in-case of inbreeding for instance.

How to humanely put down a fish:

Firstly, researchers and scientists are still to answer the question; do fish suffer when they are dying? Nonetheless, I suppose you don’t want your pet to face an agonizing death. That’s especially if you have options to reduce it.

Now that you know and have decided on what to do if a fish is dying in your tank, below are painless ways for you to humanely put down fish.

Put fish out by injection; use the vet services

This is one of the surest ways on “how to euthanize a pet fish humanely”. It’s a highly recommended way of killing fish peacefully.

It’s done by injecting Barbiturates into the fish’s system. These depressants painlessly kill off any central nervous system activity. Subsequently, death slowly occurs after its heart rate reduces following a slip into unconsciousness.   

To the public however, these are non-approved and non-accessible drugs. They are strictly a reserve of vets for such purposes.

That said, the service obviously comes at a cost on you, the fish owner.

As a result, you like most other fish keepers will easily find it rather easy to euthanize the fish yourself.

Use Clove Oil

First let’s agree; an overdose of anesthetics is the best way on how to euthanize a pet fish humanely.  Any other method can only come after.

Luckily, unlike the prescription level anesthetics, Clove oil sedative is easily available to the public. You don’t have to be a vet.

At low dosage, it is considered a good sedative and is AVMA approved. It has serious and effective numbing properties thanks to its eugenol content. Therefore, with a little potent concentration, it’s a good agent to euthanize particularly small fish.

How much clove oil to euthanize fish is needed could rightly be your next question. Well, 400mg/L is more than enough to finish the job.

The fish’s consciousness is quickly lost, followed by inability to breath. Subsequently, your fish will painlessly die of hypoxia in about 10 minutes.

Caution is however highly advised because some substances in clove oil are carcinogenic.  

How to prepare clove oil bath:
  • Get a container different, say 1 gallon size tank. Add water from the main tank to it and gently put the dying fish in.
  • Further, in a small jar/bottle (with a tight lid/cork), add water also from the main tank. Into it, add 4 – 5 drops of clove oil. With the lid tightly in place, shake the bottle till the water turns milky. You are doing this because clove oil won’t automatically mix with water but rather float.
  • Now, slowly pour the milky water into the dying fish’s water and watch as it diffuses round the container. The effect of this is that the fish now turns motionless. It has effectively been put to sleep but not necessarily dead. If you stop at that, you risk it waking up again.
  • To completely put it the fish out, repeat step II above only now with about 13 – 15 drops. This is definitely a serious overdose. Thereafter, pour out the mixture to the already knocked out fish. In about 10 – 15 minutes, your pet fish will sadly be dead. However, you’ll have most humanely euthanized your pet fish.

All said and done, from home, this is the best way to euthanize your fish quickly and in a most humane way.

Undesirable ways to put out pet fish:

Any other way you learn on how to euthanize a fish without clove oil will out rightly be inhumane. Let’s be clear on that. Nonetheless, these methods will still euthanize the fish.

They include but not limited to:

Carbon dioxide (CO2) use.

This is quick way to euthanize fish. It kills by starving the tank waters off oxygen. However, while it’ll surely put out the fish, it’s not so till about 10 minutes or so after the water is depleted of oxygen.

This is severe suffocation. It cannot honestly qualify as one of the humane ways on how to euthanize a pet fish. Though approved by AVMA, the stress on the organs in those last minutes must be terrible.

Naturally, pain is aroused when nociceptors are stimulated. The stimulation is as a result of peripheral acidosis and asphyxiation all caused by CO2. The thrashing about as if out of water is a clear indication of pain and anguish.

While adding carbonated water will still highly decrease oxygen, Alka Seltzer tablets are the most common for that.

By dropping Alka Seltzer tablets in to the water, CO2 bubbles into the water. This results after baking soda (sodium bicarbonate) and citric acid mix. The chemical reaction is instantaneous. Simply, this is how to euthanize a fish with baking soda and is mostly an easy alternative for those who opt to euthanize fish without clove oil.

However, a 30 – 45 seconds vigorous bubbling of pressurized carbon dioxide in water will equally eliminate oxygen there in. Subsequently, the fish slips into unconsciousness to its eventual death.

Other in humane methods to euthanize a dying pet fish:

It is unfortunate that some aquarist won’t care to learn ways on how to euthanize a pet fish. They couldn’t care less about painless methods of how to get rid of fish they don’t want.

All methods, mostly physical that don’t use anesthetics to put out fish are basically inhumane. You’d want to avoid them particularly to your loved pet.

These methods include but not limited to:

  • Flushing down the toilet. This is not only inhumane but also unsafe. The toxic compounds in the sewers will severely ravage before eventually putting out the fish.

The sudden exposure of the fish to drastic water quality and temperature change is just torture before death.  

Is it illegal to flush a fish down the toilet? There is no general law. However, it is in some states. Besides, it’s unsafe in that they could be carriers of disease causing organisms to native fish. How? Well, if such end up in local water ways.

  • Suffocation: Even if you don’t know what to do with unwanted fish, don’t get them out of water and watch them die. Your pet fish deserves better. The thrashing as the gills get damaged coupled with muscular pains and failing organs is surely how not to euthanize a fish.
  • Boiling in water: This doesn’t even deserve any discussion. It plainly isn’t one of the ways to put down a fish.  
  • Electrocution: Mostly, following severe body shocks by the electric currents, painful spine snapping results. Unfortunately, some fish have withstood that and wiggled “back to life” when electrocution ceases. You can only imagine the pain.
  • Snapping and pithing fish: With a blunt object and with the fish in a plastic bag, its hit hard in the head. Hopefully you do it accurately in one blow. However, you may just have hit it to painful unconsciousness.

Just to be sure, drive in a sharp object to its brain (pithing) right above the eye. Again, accuracy is important else you’ll just be inflicting more pain.

For you friend, avoid these fish euthanizing methods.

How to get rid of dead fish:

Having known how to euthanize a pet fish and having done it yourself, disposing its remains is the next thing. Remember flushing it down the toilet is not safe and could also be illegal.

So how do you get rid of dead fish? Just put it in a plastic bag and have it in the garbage. It is safe that way.

Better yet, you can dig up a small hole at the corner of your garden and burry it there.


When starting out as an aquarium fish keeper, you must be ready to do all that will keep your fish happy and healthy. This should be both in good and bad times.

Well, knowing how to euthanize a pet fish humanely is one of those calls during the bad times.

All you need to go is do it quickly and safely.

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