Doug Perrine / Hawaiian spinner dolphin (Stenella longirostris longirostris) pod, with male performing genital buzz courtship behaviour on female. A shoal of Black durgon triggerfish (Melichthys niger) swimming behi...

David Fleetham / Black triggerfish (Melichthys niger) resting on reef, displaying defensive colouration, Hawaii, Pacific Ocean.

David Hall / Black durgon (Melichthys niger) school swimming over reef, Big Island, Hawaii, Pacific Ocean.

David Hall / Waves breaking on volcanic rocks with schooling Green jacks (Caranx caballus) and Barred flagtails (Kuhlia mugil) with Black durgons (Melichthys niger) and Redtail triggerfish (Xanthichthys mento), Re...

David Hall / Waves breaking on volcanic rocks with schooling Green jacks (Caranx caballus) and a single Black durgon (Melichthys niger), Revillagigedo Islands, Mexico, Pacific Ocean.

David Hall / Waves breaking on volcanic rocks with schooling Green jacks (Caranx caballus), Barred flagtails (Kuhlia mugil) with Black durgons (Melichthys niger) and Redtail triggerfish (Xanthichthys mento), Revil...

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...

Doug Perrine / Hawaiian hogfish (Bodianus albotaeniatus) male, with Bluestripe snapper (Lutjanus kasmira), and Black durgon triggerfish (Melichthys niger) swimming over reef with juvenile Gray reef sharks (Carcharhi...

David Fleetham / Black triggerfish (Melichthys niger) swimming over reef, usually dark black in color, Hawaii, Pacific Ocean.

David Fleetham / Black triggerfish (Melichthys niger) yawning or stretch its jaws, Hawaii, Pacific Ocean.

David Fleetham / Slate pencil sea urchin (Heterocentrotus mammillatus) on a reef with Black triggerfish (Melichthys niger) and a Bluestripe snapper (Lutjanus kasmira) swimming above, Maui, Hawaii, Pacific Ocean.

Doug Perrine / Sandbar shark (Carcharhinus plumbeus), swimming toward a school of Bigeye scad (Selar crumenophthalmus). A cloud of black durgon triggerfish (Melichthys niger) follow to feed on their faeces Keauhou B...