"When it comes to the uniqueness of something, it becomes a very subjective experience.
Think about it like this: a mermaid that has spent her entire life in the ocean among the aquatic creatures will have no problem adapting to a life in some other part of the ocean.
The ocean and everything related to these waters will be a normal thing for her.
She wouldn't want to leave her house just to go to some other part of the ocean. However, what will fascinate her would undoubtedly be the land."
The mermaids are a species that actually exists within the tower. But just like the Elves and Giants, you won't see them on the lower floors.
They are restricted to the waters and even with their ability to breathe outside of water, they cannot live out of the sea for long.
(Home sickness) is a term associated with all the species that function best when they are in their natural habitat.
