Euthanasia is the deliberate ceasing of an animals life functions in a painless way so as to relive the suffering of the animal when medical aid has not helped. It is also used when culling fish that have a malformation or are not up to standards when breeding.
In the aquarium hobby various methods are used. Here is a current list.
These include: Finquel, Tricaine methanesulfonate (TMS), Benzocaine hydrochloride, MS-222, etc. Pros:
- Easy, and believed to be painless.
- Can be difficult to find. Vet prescription often required.
- If animal is removed too soon they can be revived.
- Fish have shown a stress response to some of these chemicals.
This can be put into the water via airstone, Sodium bicarbonate (Bicarbonate of soda, baking soda), health salts (Alka-Seltzer). It is not recommended for amphibians.
- Easy, and painless.
- Certain species of fish (surface breathers) and amphibians can survive in extremely low oxygen environments so the use of CO2 may not be a quick method for anaesthetising.
- Quick, easy, and painless.
- Some may have trouble finding it.
Freezing or Boiling
- May not be painless. Freezing not recommended for cold water species.
- Easily available.
- May not be painless.
Examples: Sudden blunt trauma, Decapitation, Pithing, feeding to larger fish, etc.
- If done properly can be quick.
- If not done properly can cause the animal to suffer.
- Most methods require the animal to be removed from the water first which stresses them.
Flushing down the toilet
- No special equipment needed.
- Akin to putting a puppy in an outhouse.
- Can introduce disease to your septic system and the environment.
- Animal may not die.
- The Gab on Euthanasia
- FishDoc on Euthanasia Treatments
- Euthanasia guidelines PDF file from the American Veterinary Medical Association’s (AVMA)
- RSPCA and the use of CO2
- The Krib on Euthanasia
- Fish Slaughter, Killing, and Euthanasia
- University of Washington Policy for the Euthanasia of Fish Species
- Euthanasia for Amphibians
- Don't Flush That Fish!
- Time to rethink anaesthetics?