I'm not sure specifically as I haven't read it. But it might be about a mermaid's hidden knowledge, perhaps her special powers, her relationship with the underwater world or with humans.
She could use magic. For instance, she might use a spell to make her tail disappear and look like a normal human. Also, she would need to be careful not to get wet in public, because if she does, her mermaid form might be revealed.
The Secret Garden Mermaid Story may start with a mermaid discovering the secret garden. As she explores it, she finds that the garden has a special power that can grant wishes. However, there are rules to using this power. She then has to make a choice whether to use the power for her own desires or to protect the garden and its harmony. Along the way, she meets other magical creatures that live in or near the garden, and together they face challenges and adventures.
The mermaid is surely a main character. There might also be some friendly sea creatures like a talking fish or a wise old turtle that help the mermaid in the story.
I recommend 'The Strongest Immortal Martial Great Emperor' to you. The male protagonist, Ye Bai, was the number one genius in the cultivation world on Earth. After transmigrating to the Martial Artist Continent, he slowly discovered that he was the Demon King. The female lead was a transmigrator who was not introduced in detail, and the plot was mainly based on the male lead. I hope you like this fairy's recommendation. Muah ~😗
Maybe it's about a mermaid who disguises herself as a human to attend high school and falls in love with a human student there. For example, she has to keep her mermaid identity a secret while dealing with her growing feelings for this boy.
The mermaid might have secrets like her ability to communicate with sea creatures. In a love story, perhaps a human falls in love with the mermaid. The mermaid's secret could be that she can bring good luck to the man she loves, but only if he truly loves her back.
The first episode of Mermaid's Melody was as follows:
The Lost Princess
This episode tells the story of a princess named Alice, who encountered a series of difficulties after leaving the mermaid tribe. Alice's father was a famous mage, but he unfortunately contracted a virus when he went out to see a doctor and died. In order to inherit her father's career, Alice was forced to leave the merfolk tribe and go to the palace to inherit the magic staff.
On the way out of the merfolk tribe, Alice met a human man named Kevin. He helped Alice avoid the merfolk tribe's attack and told her more information about the magic staff. In the palace, Alice met a prince named Sebastian, who was very interested in her and invited her to participate in a magic competition.
In the competition, Alice met several other contestants, including a human man named Armin and a murloc woman named Kylie. After a few rounds of competition, Alice finally won the competition, but she found out that Kelly had used a forbidden spell in the competition and Armin had disappeared in the competition. Alice began to search for Armin and Kylie and found herself caught in a conspiracy.
The Mermaid Forest
This episode recounts Alice's experience in the Mermaid Forest. The Mermaid Forest was a mysterious place filled with all kinds of mysterious creatures and magic. In the forest, Alice met a mermaid named Katja, who told Alice some secrets about the Mermaid Forest.
In the forest, Alice met a group of human explorers who were trying to find a medicine that could cure Alice's father. Alice engaged in a fierce battle with them and finally managed to escape from the Mermaid Forest.
The Ocean Kingdom
This episode tells the story of Alice's journey to the Sea Kingdom. The Sea Kingdom was a kingdom made up of mermen who lived a happy life. However, the Ocean Kingdom was facing a crisis. A human man named the Dark Prince was plotting a conspiracy to rule the entire Ocean Kingdom.
Alice decided to help the Sea Kingdom and found a merman named Albert who could help Alice find the Prince of Darkness. Along the way, Alice met a mermaid named Sarah, who told Alice some secrets about the Sea Kingdom.
I'm sorry, but the information provided by the given paragraph does not include the two novels, The Mermaid Effect and The Desaro Mermaid. I can recommend you other mermaid romance novels, such as "Young Master Li, Your Wife's Tail Loses","His Mermaid Lady Loves Candies","The Mermaid Baby in the Galaxy", and so on. I hope you like my recommendation. Muah ~