Yellow variety of bream (5)
I believe the answer is:
amber
'yellow' is the definition.
(amber is a kind of yellow)
'variety of bream' is the wordplay.
'variety of' is an anagram indicator.
'bream' with letters rearranged gives 'AMBER'.
(Other definitions for amber that I've seen before include "Yellowish translucent fossil resin" , "A yellowy resin" , "Light colour between red and green" , "Stone" , "gemstone" .)