Euthanasia

[fluttermoth]

I'd always use clove oil (25-30 drops per litre is the lethal dose, btw); it is used at lower dosages as an anaesthetic for fish, so is almost certainly painless. It's the only method which is endorsed by most vets/fish experts as being humane.

Decapitation is also quite humane, if you're sure you can do it and get it right first time. If, like me, you tend to get the 'shakes' doing that kind of thing, I really wouldn't recommend it.

 

[KISSfn]

Decapitation. Humane.

 

[NeonNeptune]

Put in a bag, and wack it or beat it with a club. Fish respond to physical force faster then chemical.

 

[FishFanatic04]

I like the previous point. There is no one who can say if clove oil hurts before they fall asleep. I know for a fact that a good hard tap while they are in a bag kills them instantly.