A fish's cognition and sensory perception are on the same level as that of other animals.
Culum Brown of Macquarie University in Australia said that although, scientists cannot provide a definitive answer on the level of consciousness for any non-human vertebrate, the extensive evidence of fish behavioral and cognitive sophistication and pain perception suggests that best practice would be to lend fish the same level of protection as any other vertebrate.
He further suggested that fishes, therefore, should be included in the 'moral circle' and should provide the protection that they deserve.
Fish have very good memories, live in complex social communities where they keep track of individuals, and can learn from one another. This helps to develop stable cultural traditions. Fish even recognize themselves and others. They also cooperate with one another and show signs of Machiavellian intelligence, such as cooperation and reconciliation, according to the study.
Fishes can build complex structures, are capable of using tools, and use the same methods for keeping track of quantities as humans do. For the most part the primary senses of fish are just as good, and in many cases, better, than that of humans. Their behavior is very much the same as that of primates, except that fish do not have the ability to imitate, the study said.
However, the researcher found that most people rarely think about fish other than as food or as pets. However, they are second only to mice in terms of the numbers used in scientific research and the more than 32,000 known species of fish far outweigh the diversity of all other vertebrates combined.
The study is published in Springer's journal Animal Cognition.