Fish in tin that's rattled (6)
I believe the answer is:
shaken
'rattled' is the definition.
(I've seen this in another clue)
'fish in tin' is the wordplay.
'fish' becomes 'hake' (hake is a kind of fish).
'in' means one lot of letters goes inside another.
'tin' becomes 'Sn' (Sn is the chemical symbol for tin).
'hake' going within 'sn' is 'SHAKEN'.
'that's' acts as a link.
(Other definitions for shaken that I've seen before include "Agitated or joggled" , "Shocked; astonished" , "Disturbed like cocktail?" , "not left undisturbed" , "Shocked, unnerved" .)