Re: What is the Most Humane Way to Euthanize a Fish?
#29
I was priviledged to sit in on a euthanasia experiment on fish by PHD student several years ago, the fish were connected up to electroreceptors and the only method that actually did work with minimal nerve response was drugging with clove oil. Even vetinary usage barbituates illicited a an electrical response interpreted as pain response from the animal, as did the use of blows, alcohol, freezing (signals recieved right until the point of death), decapitation (notably decapitation gave one of the most intense electric signals that continued for several minutes).
Basically as long as you drug it with clove oil first , rendering the fish insensible, it doesnt really matter how you kill it, beheading,freezing, impact or further drugging.Beheading is kind of the ultimate "youre not coming back from that" injury, but it depends what the keepers stomach can take.
Been using clove oil for years and they pass peacefully enough, in fact clove oil is administered at low doses and the fish falls asleep. Increase the dose and leave the fish for half an hour and it never wakes up, usually dying of asphixiation in its sleep. 20 drops per gallon kills almost any fish. Just start with 5-10 drops, wait five minutes and then put the other 10 drops in. Its easy. Knocks the fish out quicker if you whisk it up beforehand in the bucket rather than just dropping it in incidentally. It may be an oil, but it diffuses into water very well if you whisk it up.
As for zoos and humane deaths -well I did work experience at a wildlife park some 17 years ago, and back then they used to kill fish by throwing them against a wall, so dont assume that zoos always have the finest animal keeping minds at their disposal. A lot of zoos are staffed by people who accept low wages and have minimal education.
High end japanese koi breeders , german aquarists and even the americans caught onto clove oil as a way of euthanising fish decades ago, its just we in old blighty seem to have been a bit slow on the uptake.
Outside of some very expensive pharmaceuticals youd need a license to own, clove oil really is the best a home aquarist can hope for. Been using it on advice from a german aquarist for the last 20 years.
Besides £2.50 a bottle available from any chemist in the dental section, with which you could euthanise a hundred fish.Theres no reason not to use it. Ps dont buy the gel .
As for never having to use it, well we all wish that, but when you encounter diseases that are incurable yet kill slowly or you have larger fish that may take weeks to die, you'll be glad of it in the end. At least you get to know that a lifelong friend has a peaceful passing, and that in the final analysis is much better than watching a fish suffer in its final moments or having to pummel a friend . Its an unpleasant reality , but a mercy , and one I think people should always give some thought to.