Zodiac sign of the fish (6)
I believe the answer is:
pisces
'zodiac sign of the fish' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for pisces that I've seen before include "The twelfth sign of the zodiac, the fishes" , "Fish star sign" , "Twelfth sign of the zodiac, the Fish" , "Spice for the Fish" , "'Sign of the zodiac, the fish (6)'" .)