Fat Homer;4233304; said:Although i can't confirm this, but i once read that freezing is only really useful for killing fish such as Koi's, since once their body temp drops below a certain point they basically fall asleep, then as the temp drops further they die...
Yeah, I know that with us in the the koi business with the deformed culls that can't be sold while they are still small 3" and under, we place them in a shallow container with water in it, and place it in the freezer. Their body temp will eventually drop, and they will go into hibernation, and eventually pass on.
It it only painlessly successful with fish that go into a hibernation state.