One of a couple particular about eating meat or fish (5)
I believe the answer is:
sprat
'fish' is the definition.
(sprat is a kind of fish)
'one of a couple particular about eating meat' is the wordplay.
I cannot quite see how this works, but
'one' could be 'a' (a thing is one thing) and 'a' is found in the answer.
'couple' could be 'pr' and 'pr' is present in the answer.
The remaining letters 'st' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'or' acts as a link.
Can you help me to learn more?
(Other definitions for sprat that I've seen before include "Mackerel bait?" , "Traps (anag.)" , "Herring of the east North Atlantic" , "'Set a . . . . . to catch a herring'" , "chap giving richer course material to the Dutch" .)