We know in our hearts when it is time to say goodbye to an ailing animal — when the quality of life is not quality at all. Many people feel the same emotions when losing a pet koi or goldfish as they feel when they lose a furry pet such as a cat or dog — to a more or lesser degree. When a koi or goldfish gets to the point when he needs to be euthanized it most often is up to the pet’s owner to do so. We receive many calls throughout the year asking the least painful way they can put their fish to sleep. Although we don’t know for sure what a fish feels we do know what we feel and most of us want to use the least painless route.