Is there a perfect way to euthanise

[alto]

The fish should be sedated fairly rapidly and dead after 10 minutes without suffering.

I've observed some strong adverse reactions to MS-222 & clove oil, even with proper preparation
Larger fish may sedate with clove oil (& other anaesthetics) but begin to recover, so initial sedation, then pithing etc is recommended

 

[alto]

This is a decent (public access) summary article

Fish Sedation, Anesthesia, Analgesia and Ethanasia: Considerations, Methods and Types of Drugs

 

[azawaza]

Is freezing in the refrigerator a good way? I had to do it once back when I first started on one Alexrodia riesei. Was an extremely unpleasant experience though.

 

[Siege]

Is freezing in the refrigerator a good way? I had to do it once back when I first started on one Alexrodia riesei. Was an extremely unpleasant experience though.

Have a read of a quite useful article published in PFK magazine.

https://www.practicalfishkeeping.co.uk/blog/articles/painful-fish-deaths-you-might-be-guilty

 

[zozo]

Is freezing in the refrigerator a good way? I had to do it once back when I first started on one Alexrodia riesei. Was an extremely unpleasant experience though.

Not realy, it goes much to slow and probably very uncomfortable. Than throwing it with a hard smack on the floor is a more instand and less suffering quick death.. Well how wever you do it, killing something is never a nice thing to do.. What do we know what a fish feels? We can't. When you catch a fish for dinner, than hitting it behind the eyes on the skull with a heavy stick is adviced to kill it as fast as possible. For a small fish that aint an option..

Personaly if i see a fish beyond help (old age and showing weakness) i don't wait for it to die and also use clove oil, till now it always worked within minuts.
It looks like the most comfortable death also for the killer to do it.... But again what do we know about death and dying.. Zip!? We have to do it first, but nobody ever realy came back to tell. Anything near dead aint dead and wasnt dead..

 

[BubblingUnder]

Do the best you can & take comfort that whatever you do to despatch a fish it's passing will be easier than those caught on a trawler, gasping for air on the deck.

 

[alto]

I felt comfortable using clove oil (small tetras etc)
UNTIL
I needed to euthanize several Paracyprichromis nigripinnis ranging in size from 6-10 cm, subadult so not as substantial as the profile pictured fish
Though these fish had been extremely listless in the tank & container (tank water with air pump for current), when I added the diluted clove oil, they panicked & thrashed as if in agony ... slowly subsiding into unconsciousness
(then transferred to freezer as it’s difficult to ensure death with clove oil with larger fish)

 

[rebel]

We had a recent talk by a Vet who suggested clove oil or for small tropicals, sudden cold plunge ie ice water.

 

[Edvet]

Best way would be crushing/decapitation with brain destruction.