EUTHANIZING A FISH

Sometimes an illness may not be treatable,or, a fish has progressed too far into the illness to make attempting treatment worth it. In some cases choosing to euthanize a fish is more humane than trying to treat it. This section will cover all the methods step by step of humanely putting down a fish. All of these methods start by painlessly putting the fish into a deep sleep using an initial dosing of an anesthetic, although that anesthetic may also be the euthanasia agent.


When to euthanize a fish: 

How NOT to euthanize a fish:

Euthanasia Methods (with steps):

Clove Oil: 

Clove oil can be used as a sedative for aquarium fish, but can also be used as a euthanasia agent. It is extremely effective and nearly equal to MS-222 in effectiveness. Clove oil is also known to have pain killer effects on people, which means it likely has the same effect on fish. However, it should not be used as a painkiller, as misuse will kill a fish. 


CO2 Overdose:

The CO2 overdose method will NOT work with labyrinth breathing fish like a betta as they will simply take a breath of air from the surface. However this method will render the fish unconscious before it dies of suffocation in it’s sleep. 

Some people have mentioned the use of baking soda for this method of CO2 overdosing as well.

Anesthesia Overdose:

MS-222 (Tricaine methanesulfonate) and Benzocaine hydrochloride are commonly used anesthetics in the veterinary community. They are not available to the general public, but in some cases they can be legally obtained. This method involves dosing slightly more anesthetic than needed to put the fish into a sleep, so instead the fish will fall asleep and pass on.  Water hardness/temperature, animal type/size, anticipated duration of procedure can all affect the needed dosages.


You will need: Sodium bicarbonate (prevent pH spikes), MS-222 or Benzocaine hydrochloride (anesthesias).

Chart from https://www.advancedaquarist.com/2010/11/fish #99 in REFERENCES: