Quarrel about tail of puffer fish (5)
I believe the answer is:
sprat
'fish' is the definition.
(I know that sprat is a type of forage fish)
'quarrel about tail of puffer' is the wordplay.
'quarrel' becomes 'spat' (spat is a kind of quarrel).
'about' is an insertion indicator.
'tail of puffer' becomes 'r' (I can't explain this - if you can you should give a lot more credence to this answer).
'spat' placed around 'r' is 'SPRAT'.
Can you help me to learn more?
(Other definitions for sprat that I've seen before include "Traps for small fish" , "Traps (anag.)" , "Tiny fish" , "'Set a . . . . . to catch a herring'" , "Small herring-type fish" .)