"Electric" fishes (4)
I believe the answer is:
eels
'electric fishes' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for eels that I've seen before include "Long fishes" , "Water snakes twisting in lees" , "Fish (that may be jellied)" , "Else (anag.)" , "Lengthy fish" .)