Green’s Dictionary of Slang

1. (Aus.) a story.

[1674		T. Duffet Epilogue Spoken by Heccate and Three Witches 42: Have we not seen, O whorson Rogue John Dory [...] Catch’d ten times o’re with old new dress’d Story].
[a.1680		Rochester ‘The Young Statesman’ in Works of Rochester (1721) 53: These will appear such Chits in Story, / ’Twill turn all Politicks to Jests / To be repeated like John Dory, / When Fiddlers sing at Feasts].
1986		R.G. Barrett Real Thing 172: What’s your ‘John Dory’? What are you doing up here?
1992		R.G. Barrett White Shoes 257: You want the whole John Dory, do you. Well, here it is.
1999		G. Seal Lingo 90: A john dory is a story, usually with the connotation of fabrication or exaggeration.
2000		R.G. Barrett Leaving Bondi (2013) [ebook] ‘So what about you, Pie? What’s your John Dory?’.
2021		Betoota-isms 246: ‘Danny’s been liking a lot of girls’ Instagram posts lately, what’s the John Dory with him and his missus’.

2. (N.Z.) in fig. sense, one’s signature.

2003

McGill Reed Dict. of N.Z. Sl. 117: John Dory Signature, possibly rhyming slang for ‘your story’.