Franco Banfi / Shoal of Sleek unicornfish (Naso hexacanthus) Maldives, Indian Ocean

David Fleetham / Blacktongue unicornfish (Naso hexacanthus), Hawaii.

Richard Robinson / Grey Unicornfish (Naso caesius) and Sleek Unicorn fish (Naso hexacanthus ) school at Banc Lorne, New Caledonia.

Pascal Kobeh / School of Yellowback fusiliers (Caesio xanthonota) and Bluekeel unicornfish (Naso hexacanthus) Madagascar. Indian Ocean.

Jeff Rotman / Sleek / Blacktongue unicornfish (Naso hexacanthus) on coral reeef at night, Red Sea, Egypt

GEORGETTE DOUWMA / Blacktongue unicornfish (Naso hexacanthus) being cleaned by juvenile Cleaner wrasse (Labroides dimidiatus) Red Sea, Egypt.

Jeff Rotman / Blacktongue / Sleek Unicornfish (Naso hexacanthus) portrait. Egypt, Red Sea.

GEORGETTE DOUWMA / Blacktongue unicornfish {Naso hexacanthus} being cleaned by Cleaner wrasse, Red Sea

Georgette Douwma / Surgeonfish, composite image on black background, Yellowtail tang (Zebrasoma xanthurum), Powder-blue surgeonfish (Acanthurus leucosternon), Elongate surgeonfish (Acanthurus mata), Striped surgeonfish...

Georgette Douwma / Blacktongue unicornfish (Naso hexacanthus) composite image showing variation in marking on black background, Maldives, Indian Ocean.

Georgette Douwma / Surgeonfish composite image on black background, Bluespine surgeonfish (Naso unicornis), Striped surgeonfish (Acanthurus lineatus), Sailffin tang (Zebrasoma veliferum) juvenile, Mimic surgeonfish (Aca...

David Fleetham / Sleek unicornfish (Naso hexacanthus) at a cleaning station with a Hawaiian cleaner wrasse (Labroides phthirophagus), Molokini Islet, Maui, Hawaii, Pacific Ocean.