The smart answer is by touching you! But when you find out that some of the largest of these fish can knock a man over with their electric shock, the question deserves a fuller answer.
The idea of fish producing electricity as strong as this is amazing, to begin with. Yet several species have this capability. Some of the smaller ones can produce currents able to light small bulbs while some of the larger fish have powered small electric motors for some minutes before getting tired.
Some fish have generating organs in their heads. Others have them on either side of their tails. These are supplied with nerves from wither the brain or the spinal cord. In all cases the parts of the fish that produce electricity are really modified muscles. In brief bursts, however, they provide a very useful weapon. Enemies can be frightened off with a quick electric shock. And when the same shock is used to stun small fish, the electric fish does not have to look any further for supper.
Picture Credit : Google
