Fish has to dry up (6)
I believe the answer is:
turbot
'fish' is the definition.
(turbot is a kind of fish)
'to dry up' is the wordplay.
'dry' becomes 'brut' (type of wine).
'up' is a reversal indicator (in down clue: letters go upwards).
'to'+'brut'='tobrut'
'tobrut' written backwards gives 'TURBOT'.
'has' is the link.
(Other definitions for turbot that I've seen before include "Pale brown, speckled flatfish" , "Large brownish European flatfish" , "Species of flatfish" , "Expensive flatfish" , "Large succulent flatfish" .)