In case you have a bigger fish, more species, or do not have enough clove oil, then adding Alka Seltzer tablets to the unconscious fish is a humane way to put them down. This is a great option for euthanizing the fish at home since both clove oil and Alka Seltzer are readily available.
Decapitation - cutting off the head
A heavy, sharp object such as a knife breaks the spinal cord in a second and the fish instantly die without unnecessary torment. This method of euthanizing fish is found by many fish owners as the best, fastest and, therefore, the most humane. It can be used for all species.
Clove oil is a sedative which at high doses, can be used to euthanase small fish. Unlike veterinary anaesthetics, clove oil is readily available from most chemists. Around 0.4ml of clove oil per litre of aquarium water is sufficient to cause death in exposed fish.
Of the three methods that we find to be humane, the baking soda method is our least preferred. This is because some pain occurs during the process. However, many people chose this option because all that is required is baking soda and water.
Add the clove oil mixture to the container with your fish and wait. It should take less than 30 minutes before your fish's gills stop moving. Once the gills don't move for 10 minutes, the fish has been successfully put down.
Clove oil is used to anesthetize fish so that minor surgery can be performed while they're asleep. But, if you leave the fish long enough, the eugenol will kill them. This is a great way to painlessly euthanize a fish, but you have to make absolutely sure that you leave the fish exposed to the clove oil long enough.
Improper clove oil use can decrease fish viability, distort physiological data or result in mortalities.
The American Veterinary Medical Association (AVMA) accepts rapid chilling in an ice bath with water that is 2°-4°C for euthanasia of zebrafish. The fish may then be disposed of properly (no transgenic animals down the drains) and humanely.
And since the heart needs lots of oxygen to work, the bradycardia may help protect the heart muscle when there isn't as much oxygen available. Sadly, though, this still means there's no good evidence that pouring carbonated drinks on fish does them any good.
Ice-Cold Bath
Tropical fish less than 2 inches in length can be euthanized by exposing them to freezing cold water. The fish is put into a small container along with some aquarium water at the normal temperature. This container is then placed into a much larger container filled with crushed ice.
When Disease occurs: The most appropriate time to consider euthanasia, is when a disease occurs. In cases when diseases are highly contagious, or very hard to treat or even untreatable, then the old adage of one bad apple in the barrel, can be synonymous with one sick fish in the tank.
If your fish has been suffering from a severe illness and none of the treatment methods have been working, euthanasia might be the best choice. It may seem harsh to end your fish's life, but it might actually be the kindest thing you can do – especially if the fish is stressed and in pain.
Humane killing requires that the fish is stunned (rendered instantaneously insensible) before being bled out. Fish should remain in water until immediately prior to stunning. There are two methods that can be used to stun fish caught by hand: percussive stunning and spiking (also known as pithing or iki-jime).
One of the safer chemical anesthetics that can be used in anesthetizing fish is sodium bicarbonate. It is also known as baking soda and when dissolved in water, it liberates carbon dioxide, which has an anesthetic effect on fish (Bowser 2001).
Simply cleaning the tank and changing the water may help immediately save your fish. Put your goldfish in a separate tank while cleaning and replacing the water. You should clean the tank once a week to keep it from forming bacteria.
Coke contains a lot of chemical and gases. there is no way that a fish can survive.
The differences in acidity and dissolved oxygen, not to mention all of the fat, proteins, carbohydrates, and other minerals in the milk that might clog the creature's gills, would quickly spell trouble. The animal would likely die within minutes, if not sooner.
Why Fish Die After Water Change? Fish die after a water change due to sudden water shock. All aquarium fish can adjust to gradual shifts in their surroundings, but any sudden shifts from their previous environment will shock the fish, alter its internal process and stress it severely, leading to death.
Float a bag of ice or cold water in the fish tank to gently lower the water temperature. (Take care not to lower the temperature more than 2 or 3 degrees F in a 4-hour period.) Avoid putting ice cubes directly into your aquarium unless you make them with reverse osmosis or dechlorinated water.
We'd put a towel on deck, jerk the fish up on the towel, cover them up and reach under the towel and spray rum on the gills. One or two quivers, they're dead. There's no blood on deck to clean up and can be cleaned right away without worry.” Rubbing alcohol is also claimed to work the same way.
Fish are poikilothermic, meaning that their body temperature varies with the environment. When you put a fish on ice, it's body temperature drops and all it's biological functions slow down. Eventually it will die, but until then, if put back in water of the appropriate temperature it can recover.
Clove oil has the effect of numbing the nerve tissue. That happens because of the eugenol present in clove oil. Thus clove oil can act as a natural anesthetic. However, care must be taken in the application of clove oil.
Induction is most commonly achieved by immersion in a dissolved anaesthetic agent. A number of chemicals can be used for this purpose such as tricaine, benzocaine, 2-phenoxyethanol, eugenol, isoeugenol and metomidate with a range of species-specific dosing information available.