There is a wildly circulated New Yorker piece dated back from 2017 called, “I am the Tinder Guy Holding a Fish and I Will Provide for You” which is worth a read.  Go on click on the link.

Context and location are driving forces in the realisation of this category. The majority of this archive was built in London and this category, in particular, appeared on the radar when travelling to Toronto. One might acquaint Canada to wilderness, outdoor activity, and fisherman, and so this category may not seem so widely strange after all. In fact, the number of users pictured holding a freshly caught, smelly, slimy creature was astounding.

If you are viewing this category from London, seeing a fellow user pictured with a largemouth bass longer than the length of an arm, may seem out of sorts. Where could they have caught that? In the Thames? Or maybe a more logical explanation would be the Lake District? Maybe it’s not so strange after all.

The fish in online dating is a symbol of a lifestyle, a past-time, a hobby, an opportunity to let prospective matches know exactly who you are. But it is also so much more than that. This manly, noble, virile man (not usually a woman, although deviations occur, of course) holding the fish is signalling to you that he can and will provide for you and your soon-to-be family.
Dinner will always be on the table – I hope you like fish.
This is a promise of future prosperity and bliss.