Preferred Method: Clove Oil and Tank Water Method
Buy pure clove oil. You can get it at a health food store for under $10 for a ½ ounce bottle. Put the fish in a medium sized mixing bowl in his own water from his tank. In a small jar or something with a lid (I use a cleaned out jelly jar) mix the clove oil with tank water. Put the lid on and shake it like crazy over and over until the liquid in it is white.
Then pour a little into the mixing bowl with the fish. Swirl it with your hand. The fish might fight it just a little bit and then slow down. Then pour a little more in and swirl again. He should just go to sleep and appear dead. If he doesn't, try a little more of the clove solution, always shaking very well before an addition to the bowl. When he goes to sleep, leave him in the solution for a good 10 minutes and then put him in a small cup or zip-lock baggie and put him in the freezer. Pain free death. Very humane. We should all go so easily.
