Quarrel about tail of puffer fish (5)
I believe the answer is:
sprat
'fish' is the definition.
(sprat is a kind of fish)
'quarrel about tail of puffer' is the wordplay.
'quarrel' becomes 'spat' (spatting is a kind of quarrelling).
'about' indicates putting letters inside.
'tail of puffer' becomes 'r' (I can't explain this - if you can you should give a lot more credence to this answer).
'spat' going 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" .)