Platter of fish captivating king and queen (8)
I believe the answer is:
trencher
'platter' is the definition.
(term for a platter)
'fish captivating king and queen' is the wordplay.
'fish' becomes 'tench' (tench is a kind of fish).
'captivating' is an insertion indicator (I've seen this in other clues).
'king' becomes 'R' (abbreviation for rex, king in Latin).
'and' says to put letters next to each other.
'queen' becomes 'ER' (abbreviation for Elizabeth Regina).
'tench' enclosing 'r' is 'trench'.
'trench'+'er'='TRENCHER'
'of' acts as a link.
(Other definitions for trencher that I've seen before include "bearer of food" , "Plate" , "(Old) wooden platter for food" , "Don cap" , "Board" .)