Everblue (Mer Tales Book 1) by Brenda Pandos

 
 I have always loved stories about mermaids and mythical creatures, except the ones that talk about mermaids luring people to their deaths and looking like scary demons.  In Everblue you have mer people that are hardly ever around humans.  They don't mix except for basically one family.  Tatiana and Fin are mer twins that can mind speak to each other when they are in the water and have changed from their human form into mer people.  Most of the other mermaids and mermen live deep in the ocean in a city much like you would see on The Little Mermaid.  With gold and gems everywhere, what seems so beautiful is a prison for some.  Like the twins' family.  Something comes up and their parents have to relocate to the city under the ocean for a time.  Jack, their dad, has to leave on a mission and everyone else is left behind to deal with living in a city that they dislike being at.  Tatiana has the attention of the arrogant prince Azor, who wants her to be promised to him.  Once a mermaid or merman kisses someone (even if they're human) they are bonded to them.  They want to be with that person and not being together can eventually drive them both mad.  Being promised to the mer people is like being married.  In a bit of bad circumstances, Fin leaves back to his human home without permission and ends up saving his beautiful neighbor that he has liked for a long time.  The only thing is he was required to kiss her to save her life.  And now they are bonded.  Things turn for the worst when he is taken prisoner when he returns for disobeying the rules.  With his dad gone, he has no idea how he will get his family away from the city that has become a prison, and now all he wants is to be with Ashlyn, the human he is now promised to.  What's worse?  She has no idea what is going on!
  I was a little skeptical at first that the story would pull together like it did.  For a little while it seemed that you would never see how Ashlyn, Tatiana, and Fin's lives all will entwine.  But it  happens and it is a great weaving of a story together!  So if you decide to read this book, hang in there!  The story gets to be very intriguing and not the normal stuff you read about mer people!