Three goddesses kept first fish and ate second (5)
I believe the answer is:
fates
'three goddesses' is the definition.
'fates' can be an answer for 'goddesses' (I've seen this before). I am not certain of the 'three' bit.
'first fish and ate second' is the wordplay.
'first fish' becomes 'f' (sst letter of 'fish').
'and' is a charade indicator (letters next to each other).
'second' becomes 's' (common abbreviation).
'f'+'ate'+'s'='FATES'
'kept' acts as a link.
Can you help me to learn more?
(Other definitions for fates that I've seen before include "Goddesses guiding human lives" , "Mythological goddesses controlling destinies" , "Classical goddess trio" , "classical goddesses" , "Lots" .)