Crossword Genius

Which swimmer is flushing badly? (8)

Ross

I believe the answer is:

I'm a little stuck... Click here to teach me more about this clue!

'which swimmer' is the definition.
I can't judge whether this definition defines the answer.

'flushing badly?' is the wordplay.
'badly?' is an anagram indicator (I've seen 'badly' mean this).
'flushing' with letters rearranged gives 'LUNGFISH'.

'is' acts as a link.

Can you help me to learn more?

(Another definition for lungfish that I've seen is "denizens of the river".)

I've seen this clue in Sydney Morning Herald.