The electric eel, also known as the black devil fish, English name: Black Ghost Fish, more commonly known in China as the "devil knife" or "black feather". Aggressive, like to travel at night, the whole body is as black as ink, swimming dexterity, wonderful, very fast when hunting. It is black as ink, with a pointed head, a rod-like tail fin, and two white rings on the tail fin. Relying on the weak current in the body to feel the current, obstacles and food, etc., the shape is peculiar. The body shape is relatively flat, the back is smooth and curved, and the ventral and anal fins are connected to the tail in a wavy shape, like a black lace outlining the curves of the fish. The name "Devil" is more of an indication of its mysterious characteristics. Originally from Brazil, South America, the Black Devil has a gentle but aggressive character and prefers a nocturnal life. Most of the time, they hide in the darkness of densely planted water plants and crevices in rocks and submerged wood. The anal fin is broad and well-developed, connected to the ventral fin, and runs in a wavy pattern straight to the tail.