Nothing served up with starter of grilled fish (4)
I believe the answer is:
ling
'fish' is the definition.
(ling is a kind of fish)
'nothing served up with starter of grilled' is the wordplay.
'nothing' becomes 'nil' ('nil' can be a synonym of 'nothing'**).
'served up' is a reversal indicator.
'with' says to put letters next to each other.
'starter of' suggests taking the first letters.
The initial letter of 'grilled' is 'g'.
'nil' backwards is 'lin'.
'lin'+'g'='LING'
(Other definitions for ling that I've seen before include "Common heather" , "Cod-like fish" , "Slender food fish" , "Heather - fish" , "Swimmer" .)