The Wicked Blue (no jacket) (en Inglés) - Cassie Swindon

A gender reversal little mermaid standalone in modern day with steam for adults.

Eribelle is a human who has been warned to stay away from the sea, where the dangerous enemy lurks, waiting to pull anyone under. She's desperate to be away from her father, who makes all the rules in her small coastal town.

Axton is a military merman under the sea, who fails at his one and only job, which is to protect the queen. Instead he chooses to save Eribelle during a storm, a stupid human who tempted the chaotic waves in her desperate escape attempt.

Their paths are forced together in a scenario neither of them predicted.

This is the hardcover version with casebound art but no jacket