Fish could have emotions

According to a new research, fish could have emotions and consciousness. Published in Proceedings of the Royal Society of London, Biological Sciences, which has for the first time observed in fish a phenomenon known as emotional fever — the increase in body temperature when subject to stress — which has been linked to consciousness. Researchers from the Universitat Autonoma de Barcelona, together with scientists from the universities of Stirling and Bristol (UK), observed an increase in body temperature of between two and four degrees in zebrafish, when subjected to stressful situations.

Researchers divided the fish into two groups of 36 and they were placed in a large tank with different interconnected compartments with temperatures ranging from 18ºC to 35ºC.

The fish in one of these groups — the control group — were left undisturbed in the area where the temperature was at the level they prefer: 28ºC. The other group was subjected to a stressful situation: they were confined in a net inside the tank at 27ºC for 15 minutes. After this period, the group was released. While the control fish mainly stayed in the compartments at around 28ºC, the fish subjected to stress tended to move towards the compartments with a higher temperature, increasing their body temperature by two to four degrees. The researchers point to this as proof that these fish were displaying emotional fever. Some researchers argue that they cannot have consciousness as their brain is simple, lacking a cerebral cortex, and they have little capacity for learning and memory.