Puts a different spin on that fishing trip after I’ve always told myself “it’s ok, fish don’t feel pain” (to paraphrase Kurt Cobain)…
I was the first to identify the existence of nociceptors in a fish, the rainbow trout, in 2002. These are specialised receptors for detecting injury-causing stimuli, and their physiology is strikingly similar to those found in mammals, including humans. Since then, my laboratory and others across the world have shown that the physiology, neurobiology, molecular biology and brain activity that many fish species show in response to painful stimuli is comparable to mammals.
Source: There is ample evidence that fish feel pain | Fish | The Guardian