Marine iguanas seem to be everywhere in the Galapagos Islands. While snorkeling one day, I came across these guys, sunning themselves while their tails dangled in the water. Marine iguanas have longer tails than their land counterparts, allowing them to easily move through the water.
Nikon D800 with Nikkor 17-35mm lens (at 35mm) ISO 400, f/10 at 1/500th of a second, Ikelite housing with 8 inch dome port