The local fishers took thirty wild horses and placed them in an eel-infested pool. The scientist said that the Eels jumped out of the water and got into direct contact with the horse to defend their pool. Many horses died, but in the end, the eels had used up all their charges and could be easily extracted.
The story has always been disregarded as a folk tale. But Kenneth Catania, a neurologist, was pleasantly surprised when he discovered that the myth was, in fact, plausible. As he was moving the eels to a new aquarium with a net, he noticed that the fish would jump out of the water to "fight the net," much similar to the von Humboldt story.
"I thought, this is a crazy tale from 1800 that's probably totally exaggerated, if not possibly false," he said. "The Eels would periodically turn around and change from not wanting to be near the net to explosively attack it by leaping out of the water up the handle."
Catania explained that this was not a hunting technique, but a different mechanism. He explained that under water their charge was a bit lower because of the poor electric retention abilities of water. But with direct contact as the fish leaps out of the water to the supposed assailant the voltage is suddenly more intense. He explains that this was a perfect example of how fish turn a habit into character.