Arguments with scientists about fish (8)
I believe the answer is:
wrangles
'arguments' is the definition.
'with scientists about fish' is the wordplay.
'with' becomes 'w' (abbreviation).
'scientists' becomes 'rs' (Royal Society).
'about' is an insertion indicator.
'fish' becomes 'angle' (synonyms).
'rs' placed around 'angle' is 'rangles'.
'w'+'rangles'='WRANGLES'
(Other definitions for wrangles that I've seen before include "Angry exchanges" , "Disputes" .)