Castello Aragonese, a volcanic island off Naples, Italy, healthy seafloor looks like this: a lumpy quilt of red sponges, white barnacles, lilac coralline algae, sea urchins, and (near the center of the photograph) one well-camouflaged fish. It’s a tompot blenny.
Photo: David Liittschwager, National Geographic Creative.
Off shore from Castello Aragonese, Ischia, Italy, Latitude: 40.7309N, Longitude: 13.9630E