Perhaps the answer is given to the fish as it passes into the GREAT RIVER IN THE SKY. Most likely, it has to do with the fact that people often use lifestyle photos of themselves in their profiles. And they should! Its a great way to let a prospective match know who you are and what youre into.

Why do men hold fish in pictures?

Sure, biology always plays a role in our behaviors: The most basic, primitive part of our brains is focused on survival. So much of what we do comes from this foundational place. It makes sense that, even on a deeply subconscious level, men might post fish pics to poke at a primal instinct in those swiping on them.