In several arenas—legislative, academic, corporate, advocacy, and scientific—the welfare of fish has increasingly attracted attention due in part to the expansion of the aquaculture industry, as well as the growing understanding that many handling methods, management systems, and slaughter practices can induce pain and therefore reduce animal welfare. Unlike other animals raised for human consumption, however, general consensus has not always afforded fish the presupposition that they are, in fact, capable of feeling pain. The typical arguments in support of or against attributing pain capacity to fish revolve around their neuroanatomical development, behavioral and cognitive complexity, physiology, and anatomy. After reviewing the current scientific evidence and exploring the many arguments, it is irrefutably substantiated that fish are capable of experiencing pain.
Yue, Stephanie, "An HSUS Report: Fish and Pain Perception" (2008). IIA. 6.