They resemble the latter in the elongation of the body, the large number of vertebrae (240 in Gymnotus), and the absence of pelvic fins; but they differ in all the more important characters of internal structure.
Gymnotus is the only genus of - the family which possesses electric organs.
The maximum shock is given when the head and tail of the Gymnotus are in contact with different points in the surface of some other animal.
Gymnotus electricus attains a length of 3 ft.
The power of giving electric shocks has been discovered also in the Gymnotus electricus (electric eel), the Malapterurus electricus, the Trichiurus electricus, and the Tetraodon electricus.