Fishy lady from Maine -- male's captivated by bust (7)
I believe the answer is:
mermaid
'fishy lady' is the definition.
(I've seen this in another clue)
'maine male's captivated by bust' is the wordplay.
'maine' becomes 'me' (abbreviation).
'male' becomes 'm' (common abbreviation).
'captivated by' means one lot of letters goes inside another.
'bust' becomes 'raid' (synonyms).
'm' inserted into 'raid' is 'rmaid'.
'me'+'rmaid'='MERMAID'
'from' acts as a link.
(Other definitions for mermaid that I've seen before include "siren" , "'Half woman, half fish (7)'" , "Fabulous female" , "Woman-fish" , "Mythical sea dweller" .)