Sing K Little Fish Fairy Season 1

Lucia, a mermaid princess from the North Pacific, lands to find the boy she rescued from the sea seven years ago. When the boy drowned, she saved his life with a pink pearl and gave her most precious pink pearl to the boy. Seven years later, she came to land to find the former boy to get back the pearl, and finally found the boy named Kaito Domoto. However, Lucia who transformed into a human form, a girl named Lucia Nanami, was not similar to her mermaid form; she could not tell Kaito her true identity, otherwise she would turn into a bubble. So she tries hard to let Kaito figure out her true identity. At the same time, Lucia learned that a group of water monsters had invaded the sea world. She must gather the seven mermaid princesses and their pearls to resurrect the legendary ocean goddess Akane Regina and stop the water monsters' conspiracy. In order to do this, she joined forces with the other six mermaid princesses Boeing, Lina, Karen, Noelle, Coco and Sara who came to land, used their pearls to become singing idols, and used their songs as offensive weapons to deal with the water monsters.