Another article which claims that fish feel pain:
“Neurobiologists have long recognized that fish have nervous systems that comprehend and respond to pain. Fish, like “higher vertebrates,” have neurotransmitters such as endorphins that relieve suffering—the only reason for their nervous systems to produce these painkillers is to alleviate pain. Researchers have created a detailed map of more than 20 pain receptors, or “nociceptors,” in fish’s mouths and heads—including those very areas where an angler’s barbed hook would penetrate a fish’s flesh. As Dr. Stephanie Yue wrote in her position paper on fish and pain, “Pain is an evolutionary adaptation that helps individuals survive . . . . [A] trait like pain perception is not likely to suddenly disappear for one particular taxonomic class.””
"Even though fish don’t have the same brain structures that humans do—fish do not have a neocortex, for example—Dr. Ian Duncan reminds us that we “have to look at behaviour and physiology,” not just anatomy. “It’s possible for a brain to evolve in different ways,” he says. “That’s what is happening in the fish line. It’s evolved in some other ways in other parts of the brain to receive pain.”
Numerous studies in recent years have demonstrated that fish feel and react to pain. "
https://www.peta.org/issues/animals-used-for-food/factory-farming/fish/fish-feel-pain/
They are great!!
