SOLVED. YA Science Fiction / Personally read 2017 / The main character (oldest sister) has problems with her lungs and has gone through many surgeries. The two sisters find out more about themselves and their family. [s]

[Hannah]

I believe the author was either making a sequel or series out of this book.
The sisters stay in a cabin temporarilly and then move some where else. They slowly learn more about thier father and themselves.
SLIGHT SPOILER::
The sisters learn that while thier father father was protecting one he was experimenting on the other.
SPOILERS::
The oldest sister who has the breathing problems belives its her with her many past surgeries and scars. The younger sister falls sick after they had moved from the cabin. She takes and bath and feels just as good. They learn that the younger sister has gills and thier father experimented on her. The older sister was the one being protected by the surgeries.
They end up running again.

I believe that it might also involve people claiming them or thier father to be criminals but I'm not sure. Thankyou for your help, I've been trying to remeber and find this book for years!

[Marisa]

The Stellow Project?

[Hannah]

That's it!!! Thank you!