Scales (Mermaid Tales)

Scales (Mermaid Tales)
Scales in Mermaid Tales (Not in on the tail) first appeared in Episode 2: Curse of the Mermaid. When Aph is going up to land for the first time her skin starts to turn into scales. As stated by King Eric "Air is toxic". It is also shown this does not only happen to Aph, but all mermaids, stated by Tavari. Also in Episode 4: The Human World, It is shown that Human transformation does not get ride one of the scales. The scales to me almost act like scar. Also to this moment we know this can be cured with a ingredient of human hair.

What doesn't make sense is that humans and mermaids were able communicate normally. If the scales problem was always a thing, then wouldn't the mermaids never speak or discover humans? Now if this was a curse by someone or something then scales might prove valuable to the story later.

References to date:
 * 1) Episode 2: Curse of the Mermaid
 * 2) Episode 3: ...Merman
 * 3) Episode 4: Human World

Please correct me if any information is incorrect.