It would be perfectly understandable that Hailey would barely even notice her last change starting. Being already coated in scales it’s hard for her to notice them shifting about, becoming a perfect new skin for her.
Though far more noticeable is her tail growing considerably, her already thin and wide tail stretching further, becoming even bigger. Now it feels as if it had always been part of her body, stronger, and notably far better for swimming. The ugly remnants of Hailey’s former legs also undergo a change, flatting out, becoming flexible fins. Hailey’s hair prickles for a moment, changing colour to match her skin.
Welcome to our species.