Alex Mustard / Schooling Bannerfish (Heniochus diphreutes) and Yellowback fusiliers (Caesio xanthonota) diving down close to the coral reef as predators approach, North Ari Atoll, Maldives. Indian Ocean.

David Fleetham / Coral reef with Slate pencil sea urchins (Heterocentrotus mammillatus), Pennantfish (Heniochus diphreutes) and Pyramid butterflyfish (Hemitaurichthys polylepis) and a diver holding a light, Hawaii. Mo...

David Fleetham / Slate pencil sea urchins (Heterocentrotus mammillatus) Pennantfish (Heniochus diphreutes) and Pyramid butterflyfish, (Hemitaurichthys polylepis) swim through the background. Hawaii.