Fish dish taken to church in an old man's pouch (8)
I believe the answer is:
codpiece
'an old man's pouch' is the definition.
'fish dish taken to church' is the wordplay.
'fish' becomes 'cod' (cod is a kind of fish**).
'dish' becomes 'pie' (I've seen this before).
'taken to' means one lot of letters go next to another.
'church' becomes 'ce' (abbreviation for Church of England).
'cod'+'pie'+'ce'='CODPIECE'
'in' acts as a link.
(Other definitions for codpiece that I've seen before include "Medieval male accoutrement for the nether regions" , "for promotion of virility?" , "men put on centuries ago" , "What kept privates in place" , "Male dress item of former times" .)