Tim Laman / Lookdown fish (Selene vomer), captive. Nassau, New Providence Island, Bahamas.

David Shale / Trevally {Selene vomer} pelagic juvenile, West Atlantic.

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

Yva Momatiuk & John Eastcott / Tundra plants in summer, Skaftafell National Park, Iceland

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

Chien Lee / Moth (Eupterote asclepiades) camouflaged against leaf litter, Gunung Penrissen, Borneo Highlands, Malaysia

Vincent Grafhorst / Meerkat (Suricata suricatta) standing guard, Makgadikgadi, Botswana

Tim Laman / Lookdown fish (Selene vomer), captive. Nassau, New Providence Island, Bahamas.

Tim Laman / Lookdown fish (Selene vomer), captive. Nassau, New Providence Island, Bahamas.

Tim Laman / Lookdown fish (Selene vomer), captive. Nassau, New Providence Island, Bahamas.

Konrad Wothe / Gorge and stream, Alps, Upper Bavaria, Germany

Donald M. Jones / Black Bear (Ursus americanus) cub in tree, northern Alberta, Canada

David Fleetham / Sleek unicornfish (Naso hexacanthus) gathering at a cleaning station on a reef waiting for the attention of one Hawaiian cleaner wrasse (Labroides phthirophagus), Hawaii, Pacific Ocean.

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.

David Fleetham / Three Sleek unicornfish (Naso hexacanthus) at a cleaning station with a endemic Saddle wrasse, (Thalassoma duperrey) Hawaii.

David Fleetham / Sleek unicornfish (Naso hexacanthus) which has turned a darker than normal colour to help an endemic Hawaiian cleaner wrasse, (Labroides phthirophagus) spot parasites, Hawaii.