Be sparing with hot, not cold, seafood (6)
I believe the answer is:
shrimp
'seafood' is the definition.
(I know that shrimp is a seafood)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for shrimp that I've seen before include "Seafood" , "Raising of a siege" , "little fellow" , "ingredient of cocktail" , "Small prawn-like creature" .)