How to humanely euthanize a fish?

My LFS recommends freezing. I have frozen a few fish. Most fish people keep in their home aquariums are small enough that they freeze quickly. Mine have all frozen very rapidly. I just put mine in a ziplock bag and then the freezer.
 
Having never euthanized a fish before and reading over this post, I would go with clove oil because it seems the most painless and humane. Plus I am way to squeemish to chop a fish's head off or smash it. That just seems so cruel... I mean I know technically they hardly feel it, but still.
 
I don't have a quarantine tank. I'm planning and waiting it out and hoping for a miracle for her to get better or for her to die on her own. I think she has swim bladder problems, I have not seen her eat. I did see white waste on her yesterday while my other mollies have orange/red wastes. My other mollies havent been bugging her and the sick silver molly (the one in my avatar) is just hiding out by the filter.

If I wait for my silver molly to die on her own and keep her in the same tank as my others will she spread disease to my other ones?
 
I tend to keep them til they die and try what I can. If it's a spreading disease then it's already in the water anyway, so taking it out won't do much really.

Euthanizing a fish is something to make the fish keeper feel better more than the fish, so really you need to do what you think best. As I say, I tend to adopt a wait and see attitude most of the time...
 
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