How To Euthanize An Oscar Fish Humanely – With Video Instructions

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When it comes to humanely euthanizing an oscar at home, the best currently accepted method is to use Clove Oil. When exposed to Clove Oil in a sufficiently high enough dose, your oscar will firstly become unconscious before hypoxia (deprivation of oxygen) causes death. Clove Oil should be added slowly over a period of about 5 minutes, with death taking place after around 10 minutes.

Oscars are one of those fish that quickly become ‘wet pets’. They truly become one of the family. Unfortunately, there may come a time when you realize the kindest thing to do is euthanize your oscar. Obviously, we strongly recommend euthanasia of your Oscar as a last resort, but if you find yourself having to do it, it is better to do it humanely.

Euthanizing An Oscar With Clove Oil

Unlike anesthetics a veterinary surgeon may use, clove oil is readily available in medical stores and chemists. Clove oil can be purchased over the counter and without a prescription. Alternatively, clove oil can be ordered directly from Amazon (check current price)

Clove oil contains eugenol. When added in high enough concentrations to the water a fish is in, the fish will first become unconscious and then death will follow. Around 40mg of clove oil per 1 Litre of water is considered a high enough dose to cause death in fish exposed to it.

The video below shows how best to euthanize a fish using clove oil. Be aware, the video shows a goldfish being put to sleep.

Instructions For Euthanizing An Oscar With Clove Oil

  • Fill a container with aquarium water. The container should be large enough to comfortably fit your oscar in, but not so large you require large quantities of clove oil to properly euthanize your fish.
  • Carefully place your oscar into the container.
  • Mix the clove oil with some warm water. Stir to ensure oil and water are mixed as well as possible.
  • Slowly begin adding the clove oil/water mix to the container where the oscar is.
  • Continue to add the mix over a period of about 5 minutes.
  • Once your oscar appears to begin losing consciousness, add more of the mixture.
  • Keep checking your oscar. If your oscar doesn’t appear to be unconscious, add more of the mixture
  • After around 10 minutes, you should find there are no longer any gill movements.
  • Leave your oscar in the mixture for a further 10 minutes to ensure death has taken place.

Confirming Death Has Taken Place

It is generally accepted that death has taken place when there has been no gill movement for 30 minutes or more. It is important to make sure death has taken place before disposing of your oscar.

Ways NOT To Euthanize An Oscar

According to the internet, there are many ways to euthanize an Oscar. None of the methods listed below is considered humane and should never be used.

Flushing Down the Toilet

Flushing any fish down the toilet is a cruel way to euthanize it. Death will ultimately be caused by suffocation due to the fish sitting in the sewer pipes without water or by chemicals in the wastewater burning the gills. No live fish should ever be flushed down a toilet for any reason.

Ice or Boiling Water

Whilst placing your oscar into either ice cold or boiling water will certainly kill it, death would almost certainly be unnecessarily slow and painful. There is no evidence I could find to suggest putting you Oscar into very cold water ’puts them to sleep slowly’ as some forum posts would have you believe.


In theory, if you can remove an oscar’s head in one swift action, death would be instantaneous. However, Oscars, especially full-grown adults, are muscly fish and the chances of someone being able to remove the head in a single blow are slim.

Slowly cutting an Oscars head off would not be considered a humane way to euthanize and should be avoided.


Removing an oscar from the aquarium water and allowing it to simply suffocate in the air would cause immense suffering to your oscar. Suffocation is a slow, undoubtedly painful way to euthanize an oscar.

In Conclusion

It is never nice to have to euthanize any animal, especially if that animal has become part of your family. If you do find yourself in a situation where you need to euthanize your oscar, take the time to do it properly and humanely.

Using clove oil won’t cause your oscar too much distress, and your oscar will firstly become unconscious before death follows shortly afterward.

About the Author

I’ve been keeping, breeding, and showing tropical fish for nearly 30 years. Over that time I’ve done it all! I’ve had great success and I’ve made some really foolish mistakes (like the time I bought an Asain Walking Catfish). Read more…
Richard James

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