I'm sorry you had to do that. We had fish a few years ago and had some problems with our angel fish (he had some weird growth that was eating away his head). After researching our options, I think the books suggested decapitating, bringing him to a boil in a pan of water, and slamming him on the ground as hard as possible, we picked number three. It worked but it was hard to do. I wish I had known about the alka-seltzer method. That sounds the least violent.