should I put my fish out of his misery or let him die natural?

[live and let live]

So about a year and a half ago I bought this fancy goldfish.... he had a tumour on his back right by his upper dorsal fin.... it hasnt really bothered him until lately. I noticed stuff coming out of it the other day... bubbly liquid.... and for the last few days he just lays on the bottom, he isnt even coming up to eat... I am thinking his cancer ( I say that because its an obvious tumor, not ick, not infection a tumour) is getting the best of him. He is usually pretty social, eats all the time, never gives up food... but the last two days he cant seem to swim to the top. He is alone in his tank (his mate died two months ago, it was sad, he is a snuggly fish and I am not kidding) just laying there... at times gasping... I feel bad.... part of me wants to just put him out of his misery.... like cut his head off... I know gross but fast and painless I would imagine, its a sharp knife.. but the other part of me wants to let nature take its course... but he appears to be suffering.... what should I do????? I know its just a fish but if you know me, all pets that come into this house are family.... regardless of their size. And dont think my wanting to cut his head off is sadistic, its the only thing I can think of that will end his life quick and painless...

help???
Where would I get clove oil? I have never hear of this as I have never been in this situation before....

 

[Elizabeth K]

If you want to euthanize your fish please don't decapitate him.

The most humane method is to use clove oil. Fish surgeons use it to put a fish under for operations. Put your fish in a bucket along with some of his tank water. Dose the water with ten drops of clove oil per gallon. This will put him under, to actually euthanize him you need to OD him on the clove oil. Once all gill movement has ceased, he is gone.