Not crazy about recommended daily intake of fish (7)
I believe the answer is:
sardine
'fish' is the definition.
(sardine is a type of fish)
'not crazy about recommended daily intake' is the wordplay.
'not crazy' becomes 'sane' (I've seen this in another clue).
'about' is an insertion indicator.
'recommended daily intake' becomes 'rdi' (this might be a standard abbreviation of which I'm unaware).
'sane' placed around 'rdi' is 'SARDINE'.
'of' acts as a link.
Can you help me to learn more?
(Other definitions for sardine that I've seen before include "(Cramped?) fish" , "FRENCH FISH" , "Swimmer" , "Fish in tin?" , "Small fish, usually canned" .)