Marine creature reportedly towed fellow by his pants (8)

'marine creature' is the definition.
The definition and answer can be both animals as well as being singular nouns.
Perhaps there's a link between them I don't understand?

'reportedly towed fellow by his pants' is the wordplay.
'reportedly' shows a homophone (sound like).
'fellow' becomes 'f' (abbreviation - of a society etc.).
'by' says to put letters next to each other.
'pants' is an anagram indicator (UK informal term for 'nonsense' or 'rubbish').
'towed' is a homophone of 'toad'.
'his' with letters rearranged gives 'ish'.
'toad'+'f'+'ish'='TOADFISH'

Can you help me to learn more?