Swam round the fish, angry (6)
I believe the answer is:
reeled
'swam' is the definition.
The definition and answer can be both to do with motion as well as being past participle verbs.
Perhaps there's a link between them I don't understand?
'round the fish angry' is the wordplay.
'round' indicates putting letters inside.
'the fish' becomes 'eel' (eel is a type of fish).
'angry' becomes 'red' (someone may go red when angry).
'eel' placed inside 'red' is 'REELED'.
Can you help me to learn more?
(Other definitions for reeled that I've seen before include "'Staggered, spun around (6)'" , "Danced; staggered" , "Staggered - having done Irish dance?" , "Wound up" , "Staggered about in lively dance?" .)