Fish Euthanasia
There are times when it is more humane to destroy sick and injured fish than to let them slowly die by themselves. If measures to help sick fish are ineffective, it is often better to end the fish’s suffering by humane means.
What are the best ways to euthanase fish?
An overdose of anaesthetic administered by your veterinarian is a recommended method of euthanasia. The Australian Veterinary Association also states that “severance of the spinal cord, either with a scalpel or by pithing, is recommended. Pithing is recommended for fish up to 10 cm in length."
However, taking your fish to the veterinarian is not always practical, so there are some humane methods of euthanasia that fish owners can use:
Stunning fish with a sharp blow to the head, followed by decapitation is a rapid, effective, humane way to euthanase a fish, as long as it is carried out competently.
Clove oil is used to anaesthetize fish and is fatal to fish at doses greater than ¼ ml per litre of water. Clove oil is used in beer brewing and can be purchased through home-brewing outlets. It is also an aromatherapy oil, so try specialty outlets where oils are sold. Keep in mind that clove oil is classified as hazardous and can be irritating to the skin and eyes, and can be harmful if swallowed.
Since fish are cold-blooded, the brain can continue to function for a long time even after the heart and lungs have ceased functioning. Therefore it is possible for fish to recover from deep anaesthesia even if they are apparently dead because they are not breathing and have no heart beat. It can be very difficult to determine if a fish is dead, therefore, once the fish is deeply anaesthetized by leaving it in the solution for a couple of hours, it is recommended to freeze the fish, decapitate it or administer a sharp blow to the head to ensure it does not recover from anaesthesia.
What are not acceptable methods of killing fish?
Flushing fish down the toilet into the sewerage system causes slow death by exposure to toxic chemicals and water conditions.
Freezing fish is also a slow way to die and is not considered humane since the fish is not rendered rapidly insensible to pain and distress.
Taking the fish out of the water to suffocate is also not an acceptable method of killing fish.
How do I dispose of the body?
How you dispose of the body is up to the individual owner. Some prefer to bury their pets, but the body can be disposed of as normal household waste after wrapping it securely in plastic. Burning is also recommended.
- Last updated 16 November 2012
