How To Kill A Dying Tetra Humanely?

Kill a Dying Tetra Humanely

If you are reading this, you’re probably wondering how you can part farewell to your tetra buddy without giving it much pain. I know it is tough to watch your lovely pet fish suffer. You have given your all. But still, your Tetra is not bodrum escort breathing around and not eating or playing like before. Well. Sometimes, it is okay to feel like your fish deserves better than this suffering. Here’s a piece of good news: there are many ways to kill your dying tetra as humanely as possible.

Get 400mg of Clove oil and mix it with warm water. Then, pour it slowly inside the euthanizing tank over 5 minutes as the fish may get distressed. Clove oil acts like anesthesia producing painless death. There are other bodrum otele gelen escort methods of humane killing like quick decapitation, injecting anesthetics, etc.

Many people think killing a Tetra means flushing down a toilet or boiling them. But, these methods have proven to be really cruel. So today, I will help you with how you can kill your Tetra humanely, some methods to avoid, and if you should really euthanize your Tetra. Let’s dive in.

Should You Really Kill Your Tetra?

There are many factors to consider before euthanizing your Tetra. Just because your Tetra hasn’t eaten for 2 days doesn’t mean you need to kill them.

Firstly, know if you have given it your all to treat your fish by using antibiotics, water changes, anti-parasites, etc.

Moreover, look at pine coning Tetra. Tetra that is pine coning will look distended and their scales will flare away from the body. This stage is usually the late stage of many diseases and there’s no hope for better health after this.

A dying Tetra also swims at the bottom of the tank and breathes violently for air.

The decision of killing your Tetra lies in your hands. So, only after you’re sure of your Tetra suffering, should you kill your Tetra.

Let us learn when it’s time to bid farewell to your fish buddy.

Old Age

Most Tetra lives around 5 years in a tank. If you’ve had your Tetra for longer than 5 years, they act lethargic and don’t eat food or play around.

Old Tetras also have a poor immune system and succumb to many diseases. If you’re seeing these signs, your old Tetra might be suffering. And, it’s time to end their suffering.

Congenital Defects

Some Tetras are born with defects that are prone to become worse later on. Such defects are bent spine, absence of part of the body, or malformed body, etc.

Most of the time, it’s better to end their suffering at this stage rather than keep them to adulthood and suffer even more. Such fish don’t survive for long either.

Your Tetra Stops Eating Altogether

Even if you handfed your Tetras and they’re not eating for many days, chances are, they’re sick and want a break from life.

Lay On Side And Wiggle

Even if you maintain optimum conditions, some Tetra lies on their side and don’t swim around. They wiggle and lay at the bottom of the tank. It’s their time to bid farewell too.

But, there are times when if you do a 70% water change, the fish becomes alright again. So, try changing water before killing the Tetra.

How To Kill Your Dying Tetra Humanely?

Scientific research about killing a Tetra humanely is not that extensive. But, some ways have proven to be effective in killing a Tetra as humanely as possible. Let us learn them below.

Note: Always carry out the euthanization in a separate tank because the effect of the following methods might affect other fish too. Moreover, the dead fish might infect healthy fish in your tank so dispose of your fish in a safe place and quickly so. 

Clove Oil

Clove oil is an essential oil that is derived from the Syzygium aromaticum clove plant. This oil is used for treating toothache and pain reliever in humans.

Well, for Tetra though, clove oil acts as anesthesia. You can keep 0.25 – 0.50 ml of clove oil per 1 liter of water (=250 – 500 ppm) slowly over a span of 5 minutes. You can dilute the clove oil with warm water too. After your fish is sedated, it sleeps on the bottom of the tank.

You should wait for 5 more minutes to ensure that your fish has lost consciousness. After that, your Tetra will stop breathing (Look at the gills- there should be no movement of their gills). Then, dispose of the tetra immediately.

Clove oil causes painless death by hypoxia. Please remember not to put the clove oil all at once but slowly. Tetra fish tends to get stressed and may swim erratically this way. Slow and steady is the proper way.

Note: You can anesthetize your Tetra using little clove oil. Then, use the physical method after. But, 400 mg of clove oil is enough to cause the death of one Tetra fish.


Anesthetic overdose is used by veterinarians mostly. And without their approval, such anesthetic drugs are hard to receive. Moreover, euthanizing your Tetra with a vet can get really expensive. You’d rather use clove oil which is available and cheap. But, if you want to go to the vet, following anesthesia is given.


Experienced euthanizers like researchers, university experiments use Tricaine Methane Sulfonate (TMS). If you double this anesthetizing dose, you’ll achieve euthanizing dose which is enough to kill one Tetra fish.

Benzocaine HCL

Benzocaine Hydrochloride is used by veterinarians. And, this drug can’t be used without their approval. Acetone or Ethanol must be mixed with this which are components that irritate fish tissue.

Injection By Barbiturates

Barbiturate is also an anesthetic. And, injecting barbiturate in your Tetra will cause painless death. But, barbiturates are controlled drugs that aren’t available over the counter. You require a vet’s assistance for this.

Alka Seltzer

Alka Seltzer is a tablet which when inserted into water, creates CO2 bubbles. CO2 displaces oxygen from the tank. As a result, your Tetra can’t breathe oxygen and dies immediately.

For this, add 8 tablets of Alka per gallon of water.

I’ve heard people talking about Tetra thrashing using this method. And that this is an inhumane method. But, I have seen my Tetras dying instantaneously within 10 minutes.

See. I can’t prove that your Tetra won’t suffer. But, if a few minutes of suffering will release their suffering forever. And I can guarantee you that this method causes immediate and sure death.

Physical Method

Stunning, pithing, and decapitation are a humane method of killing your Tetra only if carried out correctly. Most people are scared of this method because this involves hands and force. Also, lack of skill and experience can cause poor conditions for your Tetra.

I can personally never try this method on my fish. And, I don’t recommend you to do it either. But, if these methods are done correctly, it will be humane.

How about using anesthesia first. Then try the physical method after?


Pithing is killing a fish by using a sharp-pointed weapon (like a needle, screwdriver, or pointed knife) at their brain. The site of insertion is dorsal (above) and slightly posterior (behind) to the eyes of your Tetra.


Decapitation means cutting the brain from the spinal cord to remove sensation and cause immediate death. This is done by a sharp-cutting weapon.

At the back of your Tetra’s head/operculum, you should insert the knife. After you’ve inserted the knife in there, twist the knife quickly. This causes swift and painless death.

But, if your Tetra is still not dead after decapitation, you can combine the pithing method. By inserting a knife or needle at the brain between the eyes, push forward and backward to destroy the brain.

Percussive Stunning

This method involves hitting your Tetras head with a heavy blunt weapon like a hammer or bat.

Reaching for a small Tetras head is difficult. But, if you have a large Tetra, try to blow its head off in a blow. This causes your Tetra to lose consciousness.

People use percussive stunning followed by pithing to ensure quick death in medium Tetras.

Macerate Tiny Fish

Tiny Tetras less than 2 cm can be killed by a macerator. Macerator has rotating blades which chop apart the fish instantaneously. You should use a macerator that matches the exact size of your fish.

If you have a large Tetra, I won’t recommend you to use a macerator. Maceration is only good for tiny Tetras.

What Are The Methods To Kill A Dying Tetra Inhumanely? [Not Recommended]

Now that you know the ways to kill your dying Tetra humanely, you must also understand that there are inhumane ways of killing your Tetra. You should avoid these methods at all costs!

Flushing In Toilet

You may have seen movies where kids flush down their fish to kill them. But, is this method alright? Well, the answer is a harsh no.

Flushing down your Tetra in the toilet will bring slow and painful death. This is due to the bad chemicals and cold temperature of toilet water. Especially, if your Tetra is still alive.

Is surrounding oneself with poop the way to go? I think not.

Boiling Or Freezing

Fish like Zebra Danios can be humanely killed by cold water baths because they’re small and cold-water fish.

But, if ice touched your Tetras gills, it forms very painful crystals. This is a merely slow and painful death. Oh, and also throwing your Tetra in a deep freeze when alive counts as abuse.

How about boiling though? Well, you aren’t eating your Tetra, right? Tetra fish suffer by boiling method too.

Remove From Water

Well, removing your Tetra from their tank will definitely kill them. But, is this humane? No. Tetras can utilize oxygen only when it is dissolved in water. So, your Tetras organ system will fail if you deprive your Tetra of water.

Your fish deserves better than suffocating on land.

Alcohol Overdose

Alcohol and alcohol products literally burn your Tetra’s gills. Your Tetra deserves a better death than going out by burning its gills!

Is Your Tetra Dead?

Your Tetra can be declared dead once the gill movements have stopped for 30 minutes. There is also a loss of eye-roll movement in a dead fish.

This part is very important. Because you have to ensure that your Tetra is dead before you continue with their funeral. Otherwise, you’re literally committing homicide.

How Will You Dispose Of Your Dead Tetra?

I know this will be a sad moment. But, be happy because you’re a good human being who will give a proper funeral to your beloved Tetra.

When my Tetras died, I buried them behind my backyard where they grow into peonies every year. So, you can dig up a grave for your Tetra behind your backyard.

You can also consult a veterinary and ask them to dispose of your Tetra.

I’ve heard people flush their dead fish. But, a dead fish may clog the toilet and contaminate the sewers.

Another way to bid farewell to your Tetra is by wrapping them in a plastic bag. And then, throw them in a trashcan. This is rather apathetic but you can do this method of disposal too.


How to comfort a dying fish?

You should avoid loud tapping or disturbing your Tetra when they’re in their final days. Give them peace. Provide your Tetra with nutritious and tasty food. Keep your dying buddy under direct sunlight. And try to maintain good water parameters in your tank.

Should I Flush My Fish Down A Toilet?

There are many ways to kill a dying Tetra humanely or even a dead Tetra. But, flushing is a no-no for me. Flushing an alive Tetra means it is surrounded by harsh water chemicals and bad water conditions. Nobody wants to surround oneself with poop while dying.

Final Words

I hope you’ve understood how to kill your dying Tetra as humanely as possible through this article. I mean, you gave your Tetra a good life. Thus, you should farewell your fish buddy humanely too.

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