different pq each time

Eh? In rl, that's illogical xD Humans are roughly just buoyant in regular water. If the fluid they're swimming in is even denser than water, then the buoyant force is even stronger. If you want them to sink, then you'd want something less dense than water (actually human body density) such as alcohol.

*is being nerdy*

lol Hey! I didn't make up the description the statue tells you. That's just what it says. He says the water is so dense, you can't swim in it.
Ask NxProse to explain it.