Alex Mustard / Male Bullethead parrotfish (Chlorurus sordidus) displaying in late afternoon. Ras Katy, Sinai, Egypt. Gulf of Aqaba, Red Sea.

Jeff Rotman / Bullethead parrotfish (Chlororus sordidus) tail. Red Sea, Egypt

Jeff Rotman / Bullethead Parrotfish (Scarus sordidus) portrait at night. Egypt, Red Sea.

Alex Mustard / Bullethead parrotfish (Chlorurus sordidus) male, close up of eye, whilst sleeping at night. The Alternatives, Sinai, Egypt. Red Sea

Pascal Kobeh / Close-up of the head of Bullethead parrotfish (Chlorurus sordidus) sleeping at night in its mucus cocoon, Great Barrier Reef, Australia. Coral sea.

Pascal Kobeh / Close-up of the head of a Bullethead parrotfish (Chlorurus sordidus) sleeping at night, Great Barrier Reef, Australia. Coral sea.

Alex Mustard / The detail of an eye of Bullethead parotfish (Chlorurus sordidus) taken at night. Gubal Barge Wreck, Gubal Island, Egypt. Strait Of Gubal, Egypt.

GEORGETTE DOUWMA / Parrotfish {Scarus sordidus} feeding on coral, Red Sea

GEORGETTE DOUWMA / Bullethead parrotfish grazing on coral {Scarus sordidus} Red Sea, Egypt

GEORGETTE DOUWMA / Bullethead parrotfish sleeping in cocoon of mucus at night {Scarus sordidus} coral reef, Red Sea

Jeff Rotman / Bullethead parrotfish {Scarus sordidus} Red Sea

Jeff Rotman / Bullethead parrotfish {Scarus sordidus} on reef, Red Sea