Little Saint Nautilus by Duckie Mack

Cory’s dream of being a professional surfer was cut short when he was injured from an accident. Despite losing his career, he can’t stay away from the water, always searching for the face of the man who rescued him. Was he real or a figment of his imagination?
Nemo is a nautilus shifter who has lived his life at sea, keeping his distance from humans, until he couldn’t resist helping one. He never forgot the man he saved, and he returns to the same beach each year, looking for him.
When Nemo finds Cory, he risks everything to be with him, even his shell. Without it, he can’t return to the sea.
Cory can’t believe his dream man is real. He’s captivated by him, and is willing to do anything to keep him. Except, the thing Nemo needs most is the home he lost.
Nemo soon discovers the wonders on land he didn’t know existed. But the greatest wonder is Cory, who shows him what home really means.