Rays and sharks can turn neon green, while nearby coral come alive in electric reds. And hawksbill sea turtles? Under ultraviolet light, they turn into glow-in-the-dark, underwater Christmas ...

Green turtles are olive-green above, usually variegated with brown, reddish-brown and black. They are whitish or cream below. The green turtle is named for the greenish colour of its fat, caused by ...