Joel Sartore / Photo Ark / Whitecheek surgeonfish (Acanthurus nigricans) portrait, The National Aquarium, Abu Dhabi. Captive, occurs in Pacific Ocean.

Joel Sartore / Photo Ark / Dussumier's surgeonfish (Acanthurus dussumieri) portrait, Aquarium of Boise. Captive, occurs in Indo-Pacific.

David Fleetham / Orangeband surgeonfish (Acanthurus olivaceus) visiting cleaning station of Hawaiian cleaner wrasse (Labroides phthirophagus).They change colour to expose parasites, some turning black and others turni...

David Hall / Yellow tangs (Zebrasoma flavescens) and Brown surgeonfish (Acanthurus nigrofuscus) cleaning a Green sea turtle (Chelonia mydas) at "cleaning station", feeding on alage on turtle's skin and shell,...

Tui De Roy / Razor surgeonfish (Prionurus laticlavius), Blacktip cardinalfish (Apogon atradorsatus) and Black-striped salema (Xenocys jessiae) swimming over coral reef. Galapagos Islands, Ecuador. Pacific Ocean...

David Fleetham / Orangeband surgeonfish (Acanthurus olivaceus) pair swimming through coral reef, Hawaii, Pacific Ocean.

Doug Perrine / Green sea turtle (Chelonia mydas) being cleaned of algae by Yellow tangs (Zebrasoma flavescens), Chevron tangs (Ctenochaetus hawaiiensis), Black durgon triggerfish (Melichthys niger) and Parrotfish (S...

David Fleetham / Black surgeonfish (Ctenochaetus hawaiiensis) portrait, Hawaii, Pacific Ocean.

Doug Perrine / Female Blackstripe Coris (Coris flavovittata) with Goldring surgeonfish (Ctenochaetus strigosus) and Yellow tangs (Zebrasoma flavescens) on a reef, South Kona, Hawaii, Pacific Ocean.

Georgette Douwma / RF - Composite image of blue tropical reef fish on a black background, Blue triggerfish (Pseudobalistes fuscus), Elonggate surgeonfish (Acanthurus mata), Yellowtail tang (Zebrasoma xanthurum), Neon da...

Georgette Douwma / RF - Composite image of tropical reef fish on a black background, Rusty parrotfish (Scarus ferrugineus), Striped surgeonfish (Acanthurus lineatus), Saddleback butterflyfish (Chaetodon falcula), Seahor...

Georgette Douwma / RF - Tropical reef fish, composite image on a black background, Mimic surgeonfish (Acanthurus pyroferus), Elongate surgeonfish (Acanthurus mata), Redmouth triggerfish (Odonus niger), Black spotted por...