This is a topic with a lot of contention… And im 100% sure im going to offend someone from this suggestion, and for that I am sorry to you. But IMHO I feel this suggestion is best…. It is NOT for the faint of heart, some would say its cruel, but from the perspective of the fish (isn’t that the creature we are concerned with, NOT the people who live on?) it is FAST, and 100% dead every time, no 1/2 kills, no suffering, and no 15 minutes of being frozen alive, drugged etc…
If you sole concern is having the fish not suffer then this is what I would do: put the fish in a glass, get a pair of boots with little to no tread. Go outside onto the concrete, pour the fish on the concrete and immediately stomp it.
The CNS (central nervous system) is destroyed immediately, if the neurons are spread out over your shoe then they can’t talk to one another, thus the fish ceases to be…
From the perspective of the fish, it was sitting in a cup looking at the world… then it was being poured, and while its gills are still wet suddenly it is no more…
NOW from the perspective of most people watching this, it may not be considered humane; but that IMO is because of the imagery involved, remember how the fish looks after the fact has no bearing on what the fish feels. It is simply the queasiness of the passerby, if you don’t see gore then it must be a good death….. Well if it was I who was being “euthanasied” I would much rather have it all over in a fraction of a second then a 25 minute routine of being drugged to death etc… Then again most people don’t like the idea of watching someone get shot in the head with a shotgun…. It looks yucky and make people vomit… but think of what the brain thinks while being drugged, frozen, electrocuted, etc…
IMO if you are going to do it, do it fast and with a lot of force….