Treat tripe and fish that's sent back (6)
I believe the answer is:
doctor
'treat' is the definition.
(I know that doctor is a kind of the treat)
'tripe and fish that's sent back' is the wordplay.
'tripe' becomes 'rot' (I've seen this in another clue).
'and' says to put letters next to each other.
'fish' becomes 'cod' (type of fish).
'that's sent back' is a reversal indicator.
'rot'+'cod'='rotcod'
'rotcod' reversed gives 'DOCTOR'.
(Other definitions for doctor that I've seen before include "Who, for example" , "Physician" , "Ship's cook" , "bones" , "Medical specialist" .)