User blog comment:Fliu/Chapter 978: Enter the Belly of the Beast/@comment-189.60.206.191-20200428031707/@comment-108.83.222.210-20200430181342

Interesting possibilities. As a rule, I agree that Fish-Men generally function better without losing their ability to swim. Still, it is a possibility that Sasaki has a devil fruit that is considered a fair exchange. A matter of perspective of course given that any devil fruit can become a powerful asset if the user is creative enough.