Set around lunchtime, for fish (6)
I believe the answer is:
plaice
'for fish' is the definition.
(plaice is a kind of fish)
'set around lunchtime' is the wordplay.
I cannot quite understand how this works, but
'around' could be 'c' (abbreviation for 'circa') and 'c' is present in the answer.
'lunchtime' could be 'i' (one o'clock is I on a clock with Roman numerals) and 'i' is found in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for plaice that I've seen before include "Flatfish; sounds like put" , "Location of the fish" , "A fish; sounds like put" , "Type of fish" , "Flat fare" .)