system
A chat on subreddit /r/NoStupidQuestions
human
They may not scream, but they writhe. And for a long time there was a myth, probably still perpetuated, that fish don't feel pain. Now, looking at the nervous system, it seems blatantly obvious that they do, and consensus is they feel more pain.

Theres a 3 step process to kill a fish with minimal pain and maximum efficiency but I've never done it and dont know what it's called.
gpt
Which study shows that? The one out of Germany a few years ago showed they lacked the nervous system to experience pain as we know it. There have been studies that suggest they are more sensitive to pressure than we are, but not pain as we know it.