Fish have heartaches too ZdS#30

The Youtube channel Zeste de science explores all aspects of scientific research, proving that even the most complicated scientific facts can be explained in less than 5 minutes, and that even the most seemingly trivial events of everyday life, if thoroughly studied, can contribute to the biggest technological advances.
Episode 30: A research team developed an experiment to study emotions in a particular species of fish, the convict cichlids. The females are trained to receive two boxes in their aquarium, one with a white lid, the second with a black lid. Little by little, the fish understand that only the box with a white lid contains a reward. It is therefore opened systematically. Creating an ambivalent situation with a box with a grey lid makes it possible to measure the animal's degree of optimism based on its reactions. These small tropical fish are known to be monogamous. Therefore, a decrease in optimism is observed in the female when forced apart from its breeding male.