Cool! You know oscars need giant tanks, like 75g right? lol I guess, I've only ever euthanized a fish once, one of my guppies, as it had fish tuberculosis. I used the hammer method, as it looked the quickest and least painful to fishy.

Feeding them to oscars is a good idea. With the culls from my platy fry I kept them in their own small tank, but I guess most don't have the room to do that.