Patrick was amazed as he transformed. Not only were his legs merging into a single, fish like tail, but he was getting younger. His body hair receded, his public hair vanished, and his receding hairline grew back. His overweight body fat shriveled away. His vision blurred. The glasses he had needed for years to see clearly were no longer working. He cast them aside to see clearly.
As he grew younger, his face cleared. His facial hair fell off. His adult teeth fell out as his baby teeth regrew in their place. His brown hair lightened to a blond color he hadn't seen since his youth. He looked in the water to see his aging stopped at 6 years of age. However, his human body, while that of a 6 year old, was quite muscular, like one of those child body builders he'd seen pictures of.
The mermaids helped him move deeper into the water, awwwing at how adorable he looked.
Patrick smiled, giddy with excitement as he moved his forest green tail to and fro.
"I take it your happy?" The lead mermaid asked with a smile. "Yes. I get a chance to be a kid again." He laughed.
"You'll find life under the sea to be more worry free. No nine to five jobs, no stress of city life. Just bliss." She smiled as she began teaching Patrick how to swim.