All animals are somebody—someone with a life of their own. Behind those eyes is a story, the story of their life in their world as they experience it. In our culture, we have been encouraged to think of animals as things, as commodities. The great challenge lies in having a change of perception. The realization that they have a life of their own, independent of their utility to me or to anyone else: this is what I am trying to get at when I speak of them as being “subjects of a life.” In this sense, they are exactly like us, equal to us. — Tom Regan
Fish have a complex nervous system that allows them to feel pain just as other animal species. And just as any other sentient being on this planet, including humans, fish fear pain and want to avoid it as much as possible.