Haddock official

A grouse once whose surname sumame? was haddock
Quite terrified by Fanny Craddock
Filled his shoes with cement and
Said "That's not what I meant", and
"There's kangaroos in the top paddock!"

There once was a chap who about
The referential admitted no doubt
His naive faith in history
Was rather a mystery too large a tail? tale?
Preposterous and inside-out!

A girl with the name Beaumont Bissell
Found an oil-covered eye made her whistle,
So in terrible fear,
She replaced that old see(e)r
With a haddock, which made it official.

To "explain":

         OIL or O{eye}L
                   |
                   V
    O"FISH"L or O{fish}L