Gary Bell/ Oceanwide / Painted Sweetlips (Diagramma pictum) in Slender Cardinalfish (Rhabdamia gracilis) school, Great Barrier Reef, Australia

Gary Bell/ Oceanwide / Painted Sweetlips (Diagramma pictum) in Slender Cardinalfish (Rhabdamia gracilis) school near Double-headed Maori Wrasse (Cheilinus undulatus), Great Barrier Reef, Australia

Gary Bell/ Oceanwide / Double-headed Maori Wrasse (Cheilinus undulatus), Painted Sweetlips (Diagramma pictum), and Slender Cardinalfish (Rhabdamia gracilis) school, Great Barrier Reef, Queensland, Australia

Marie Read / Ruby-throated Hummingbird (Archilocus colubris), male flying in to feed from cardinal flowers (Lobelia cardinalis) New York, USA. August.

Marie Read / Northern cardinal (Cardinalis cardinalis) male perched amid snow-covered branches, New York, USA, February.

Alan Murphy/ BIA / Northern Cardinal (Cardinalis cardinalis) male and Pyrrhuloxia (Cardinalis sinuatus) male fighting, Texas

Alan Murphy/ BIA / Northern Cardinal (Cardinalis cardinalis) female flying, Texas

Donald M. Jones / Pyrrhuloxia (Cardinalis sinuatus) male feeding on Ocotillo (Fouquieria splendens) flowers, southern Arizona

Alan Murphy / Pyrrhuloxia (Cardinalis sinuatus) male, Texas

Alan Murphy / Northern Cardinal (Cardinalis cardinalis) male, Texas

Alan Murphy / Pyrrhuloxia (Cardinalis sinuatus) female, Texas

Martin Dohrn / Cardinal fish (Apogon sp) moments after it has mistakenly tried to eat an ostracod. The ostracod then releases glowing mucus that is so bright that it can be seen through the body of the fish. This gi...