It's to Aqua's benefit too, it seems. Had he been able to tell that Su-jin is a much bigger predator than a regular human, Aqua probably would've avoided him. He would've missed out on these interactions and would've missed out on the chance to learn how to read! He would've pre-judged someone who is being very kind to him based solely on scent. Not a terrible thing for an animal that is often prey, but not great for a human-shaped animal who wants to befriend those on land.

Aqua blinks up at Su-jin, then looks in the direction he's pointing before doing the same with his own free hand, pointing straight above them. "Oh. Noon is a mid-day time when the sun is straight overhead. Let's meet around noon time tomorrow!"