The fish use reacting behavioural mechanism in order to protect itself from the danger.
The fish uses reacting behavioural mechanism when the fish sense any type of danger surrounds it. This behaviour is a type of defense mechanisms which is used to defend and protect itself.
The fish apply electric shock in order to protect itself from the attackers and give harm to the other organisms which comes in contact with it so we can conclude that the fish use reacting behavioural mechanism in order to protect itself from the danger.