Alex Mustard / A male pajama cardinalfish (Sphaeramia nematoptera) incubating eggs in his mouth (not clearly visible). Bitung, North Sulawesi, Indonesia. Lembeh Strait, Molucca Sea.

Georgette Douwma / Pajama cardinalfish (Sphaeramia nematoptera) Indonesia.

Georgette Douwma / Pajama cardinalfish (Sphaeramia nematoptera) West Papua, Indonesia

Georgette Douwma / Pajama cardinalfish (Sphaeramia nematoptera) Lembeh Strait, Sulawesi, Indonesia.

Joel Sartore / Photo Ark / Pajama cardinalfish (Sphaeramia nematoptera) portrait, Omaha's Henry Doorly Zoo and Aquarium. Captive, occurs in Western Pacific Ocean.

Joel Sartore / Photo Ark / Pajama cardinalfish (Sphaeramia nematoptera) portrait, Omaha's Henry Doorly Zoo and Aquarium. Captive, occurs in Western Pacific Ocean.

Georgette Douwma / Tropical reef fish composite image on black background, Splendid soldierfish (Myripristis melanosticta), Pajama cardinalfish (Sphaeramia nematoptera), Golden puffer (Arothron meleagris), Banggai cardi...

Georgette Douwma / Yellow tropical reef fish composite image on black background, Falcula butterflyfish (Chaetodon falcula), Yellow boxfish (Ostracion cubicus), Golden butterflyfish (Chaetodon semilarvatus), Red Sea clo...

Georgette Douwma / Yellow tropical reef fish composite image on black background, Sailfin tang (Zebrasoma veliferum) juvenile, Pajama cardinalfish (Sphaeramia nematoptera), Three-spot angelfish (Apolemichthys trimaculat...

Frederique Olivier / Pajama cardinalfish (Sphaeramia nematoptera) amongst Mangrove (Rhizophora) roots, Uepi Island, Solomon Islands.

David Fleetham / Pajama cardinalfish (Sphaeramia nematoptera) at night off the island of Yap, Micronesia.