Shrimp relative (5)
I believe the answer is:
prawn
'shrimp relative' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for prawn that I've seen before include "Small, edible crustacean" , "Small tasty crustacean, nice in cocktail" , "Shellfish" , "Cocktail ingredient" , "Popular oriental snack" .)