Fish cognitive research has revealed sophisticated learning, problem-solving, and social intelligence that transforms our understanding of their welfare needs and capacity for suffering.
Fish cognition research has comprehensively overturned the assumption that fish are simple reactive organisms. They demonstrate learning, memory, problem-solving, social learning, and individual personality differences that indicate rich inner lives. The question is not whether fish can suffer but how much and in what ways. Pain responses in fish including behavioral change, analgesic seeking, and sensitization to repeated injury mirror mammalian pain responses. Cognitive complexity means that fish welfare in captivity and fisheries involves more than simply preventing physical injury. Social species including cichlids and damselfish suffer from isolation. Territoriality means inappropriate social pairing causes chronic stress. Complexity and stimulation needs are real in cognitively sophisticated fish species.