The little mermaid, an undine, is an elemental spirit of water.  

In her story, she has to deal with her identity and goes further than anyone before.

She is giving her heart to a human prince.

In her hope to receive a human, immortal soul.

Not knowing the outcome she gives up her fin, the most iridescent part of her identity, and her voice.

Not does she see that she has something far greater: the soul of  an immortal water spirit. 

An opalescent identity that she can express with her true voice.

As she gives up her voice, she loses the chance to tell the prince of her love.

The search for her true self continues. 

Until she turns into the mist of the sea and transforms to a sylph, an air spirit. 

Finally, she reaches the immortality she sought.