Goldfish and Aquarium Board Articles
Euthanasia
By Jo


Perhaps the kindest thing you can do for a pet fish that is extremely ill or severely injured is to induce its death humanely through euthanasia.

There are many misconceptions on the web on how to euthanize a fish. Our recommendations follow the American Veterinary Medical Association (AVMA) recommendations of overdose as a preferred and humane method for euthanasia.

The following methods are recommended in order of preference:

Finquel (MS-222)
Finquel is our preferred method for euthanizing a fish. With Finquel the fish should fall asleep peacefully. Other methods including clove oil, baking soda and alka seltzer may be irritating and cause stress prior to death. You won't be able to find Finquel in your local pet stores, so we recommend ordering it online to have it on hand for emergencies. However, in countries outside the US, you may need a prescription to buy it. Sources for obtaining Finquel include:


Finquel(MS-222 or Tricaine Methanesulfonate) is a fish sedative and an anesthetic. Choose a container large enough that the fish can move around freely. Use equal amounts of Finquel and baking soda (to buffer the solution as Finquel can make the water acidic). Mix 1/2 teaspoon of Finquel and 1/2 teaspoon of baking soda per 1 gallon (3.84 liters) of dechlorinated water in the container and then add the fish. If the fish is still moving around after 10 minutes you can add another 1/2 teaspoon of Finquel and and 1/2 teaspoon of baking soda predissolved in some water from the container. Once the fish turns on its side, watch the opercular movements (respiration/gill movements). The fish should be removed from the solution after at least ten minutes have passed since the last observed opercular movements (respiration/gill movements).

Oil Of Clove
Add 12 drops of Oil of Clove per 1 gallon (3.84 liters) of dechlorinated water. Oil of clove is very hard to mix so you may want to emulsify the clove oil by placing it in a smaller amount of water in a glass jar and shake well. Place the fish in a container large enough for it to move around freely along with an airstone on the highest setting and add the clove oil solution. The airstone will help keep the clove oil in solution. Once the fish turns on its side, watch the opercular movements (respiration/gill movements). The fish should be removed from the solution after at least ten minutes have passed since the last observed opercular movements (respiration/gill movements).

Baking Soda
When dosed properly, baking soda (sodium bicarbonate) causes rapid loss of consciousness and death by increasing the amount of carbon dioxide in the water. Place the fish in a container large enough for it to move around freely. Mix a solution of 3 tablespoons of baking soda to each quart (0.9463 liter) of water and then pour into the holding container. Once the fish turns on its side, watch the opercular movements (respiration/gill movements). The fish should be removed from the solution after at least ten minutes have passed since the last observed opercular movements (respiration/gill movements).

Alka-Seltzer
Alka-Seltzer can be also be used to produce carbon dioxide in the water and induce loss consciousness and death. Choose a container large enough so the fish has room enough to move freely. Use 1 tablet/5 gallons (18.93 liters) or 2 tablets/ 10 gallons (37.85 liters) of dechlorinated water and then add the fish to the solution. Once the fish turns on its side, watch the opercular movements (respiration/gill movements). The fish should be removed from the solution after at least ten minutes have passed since the last observed opercular movements (respiration/gill movements).

The following methods are NOT recommended

Freezing
Freezing is very painful to the fish as ice crystals are formed in the body tissue and bloodstream.

Vodka And Oil Of Clove
The combination can be used IF done properly but the majority of the cases of at home euthanasia the fishes gills are burned by the vodka causing a violent death.

Euthanasia Policy References:

  1. Canadian Council on Animal Care, Guide Vol. 1 (2nd Ed.). 1993. Chapter XII Euthanasia.
  2. Report of the AVMA Panel of Euthanasia. 2000. Journal of American Veterinary Medical Association 218(5): 670-696.
  3. Report of the AVMA Panel of Euthanasia. 1993. Journal of American Veterinary Medical Association 202(2): 230-249.
  4. Stoskopf, M.K. 1993. Fish Medicine. W.B. Saunders Co. Philadelphia.
  5. The Guide for the Care and Use of Laboratory Animals. 1996. National Academy Press, Washington, D.C.
  6. Noga, E.J. 1996. Fish Diseases: Diagnosis and Treatment. Mosby-YearBook, Inc, St. Louis.
  7. Casebolt, D.B., D.J. Speare, and B.S. Horney. 1998 Care and Use of Fish as Laboratory Animals: Current State of Knowledge. Lab Animal Science 48(2): 124-136.
  8. Burns R, McMahan B. Euthanasia methods for ectothermic vertebrates. In: Bonagura JD, ed. Continuing veterinary therapy XII. Philadelphia: WB Saunders Co. 1995:1379-1381.

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