Claudio Contreras / Barspot cardinalfish (Apogon retrosella), El Violin, Huatulco Bays National Park, southern Mexico, November

Joel Sartore / Photo Ark / Barspot cardinalfish (Apogon retrosella) portrait, Downtown Aquarium Denver. Captive, occurs in Eastern Pacific Ocean.

Joel Sartore / Photo Ark / Barspot cardinalfish (Apogon retrosella) portrait, Downtown Aquarium Denver. Captive, occurs in Eastern Pacific Ocean.

Claudio Contreras / Barspot cardinalfish (Apogon retrosella), San Rafaelito Lighthouse Islet, Balandra National Protected Area, near La Paz, Gulf of California (Sea of Cortez), Mexico, September