Good swimmer hauled up Joy
I believe the answer is:
glee
'joy' is the definition.
(I've seen this in another clue)
'good swimmer hauled up' is the wordplay.
'good' becomes 'g' (abbreviation).
'swimmer' becomes 'eel' (eel is a kind of fish).
'hauled up' says the letters should be written in reverse.
'eel' backwards is 'lee'.
'g'+'lee'='GLEE'
(Other definitions for glee that I've seen before include "Merriment or gloating" , "(Malicious) satisfaction" , "Great joy" , "Elation" , "Impish enjoyment" .)