More information about Electric Eels
Physical description

  • Typical eel has olive brown body color with yellow spots. 
  • Long, slender, snakelike shape. 
  • No scales. 
  • Elongate anal fins.
  • No dorsal or pelvic fins
  • Body length up to be almost 8 feet (2.5m) long. 
  • Weigh up to 60 pounds.
  • No teeth
  • Males live about 10-15 yr..
  • Females live about 12-22 yrs. 

  • Diagram of Electric eel courtesy

    General information:

    The electric eel is not a true eel.  They are members of a group of electrical fish that includes the knife fish and the ghost fish, both of which can also be seen at the Record Aquarium..  Their closest relatives outside of this group of electric fish are the catfish.  An electric catfish can also be seen at the Aquarium.  As can be seen from the diagram above, an electric eel is mostly tail.  The internal organs are compressed into the anterior 1/8th of the body, and the rest of the fish consists of the long, electricity-producing tail.  Extending down the entire tail region is an elongated anal fin.  There is no dorsal fin. 

    Electric eels are not aggressive; They may produce a damaging shock when surprised or stepped on, but the primary use of its electrical talent is to repel potential predators or to immobilize their own prey.  Although electric eels can grow to be large fish, their prey is usually a small creature that can be managed without teeth.  The most common food item for electric eels is other fish. 

             Photo courtesy of Dr. William Fink
    Click here for a short film demonstrating swimming motion of an electric eel
    Film courtesy of Dr. William Fink
    Special anatomical, physiological 
    or behavioral adaptations:

    Like all electric fish, electric eels use the production and sensing of weak electrical signals for navigation and for social communication with other electric eels in dark or murky waters.   The fish have small eyes and poor eyesight, which worsens as the fish ages.  The electrical sensors are a modification of the lateral line, a row of pits that fish usually use as pressure sensors.  The lateral line can be seen in the picture above just at the margin of the more darkly pigmented dorsal side of the fish.  The fishes' reading of their electrical environment is something like echolocation in bats or in dolphins.  Some of the electrical receptors are tuned to the transmissions of non-electrical fish; others are specialized for detecting the signals of the fish itself.  Their ability to detect electrical signals even allows them to detect the heartbeat of other fish.  They get the best "picture" of their surroundings if the body is held relatively rigid.  The rippling anal fin allows the animal to propel itself through the water with little side-to-side bending of the body.  The presence of pollutants in the water can alter the signal emitted by the fish, and a study in France is testing the possibility of using the fish to monitor water quality.

    The electric eel is different from other electric fish in its ability to generate a stunning or even a killing electrical discharge.  The electric eel can produce up to 600V in a single dischange -- this is 5 times the shock you would get from sticking your finger into an electrical socket.  David Attenborough, in his TV series Life On Earth, demonstrated how the electrical current produced by an electric eel could be used to turn one of more light bulbs!  The electric organ, which consists of a series of modified tail muscles, is similar to a row of batteries connected in a series.   It is subdivided into three sections:  two small and one large.  One small battery is used for navigational signals.  The large battery and the other small one is used to generate the stunning discharge.  After delivering a strong shock, the electric eel must then allow the electric organ to recharge.   Batteries have to be recharged using an external source of energy; in the electric eel the energy to recharge the electric organ comes from the fish's metabolism. 

    A discharge from an electric eel can kill the small fish that are its primary food, but electric eels can also shock potential predators.  A touch from the electric eel's tail can effectively disable a human or a large animal with a stunning shock, although a single discharge is usually not enough to kill.   However repeated shocks could kill, and falling over in the water after a disabling discharge could result in drowning.  An electric eel would NOT make a good pet! 

    Electric eels are air-breathing fish that use vascular folds in the lining of the mouth for absorbing oxygen.  Air is taken in through the mouth and out through the gill slits.  If you watch the fish in the Record Aquarium for a few minutes, you will see it rise to the surface to breath.  Nearly 80% of the oxygen used by the fish is taken in this way. 


    Ask the Experts at Scientific American:
    How do electric eels generate a voltage and
    why do they not get shocked in the process?

    Personal Observations: When first observing the electric eel, he had very little motion.  then, he would swim to the top with its head upward.  He would stay on top of the water for a few seconds, navigate around the water, then swim into a corner and stay there for a few minutes.  The electric eel repeats the cycle of swimming to the top of the water, navigating the floor of the tank, and then lying still in a cormer of the tank throughout the time he was observed.

    Electric eel:  Main Page
    Sources and Links

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    Fish at the Fort Worth Zoo