Alex Mustard / A male Yellow-headed jawfish (Opistognathus aurifrons) blowing out a clutch of eggs he has been incubating in his mouth in order to oxygenate them, East End, Grand Cayman, Cayman Islands, British West...

Alex Mustard / Banded jawfish (Opistognathus macrognathus) male incubating eggs in mouth, which are at a late stage of development and will soon be ready for release. West Palm Beach, Gulf Stream, West Atlantic Ocea...

Doug Perrine / Ring-eye jawfish male expels larvae after brooding eggs in mouth for a week {Opistognathus sp} Borneo (Non-ex).

Georgette Douwma / Gold specs jawfish male incubating eggs in mouth, unable to feed {Opistognathus sp} Sangalakki, Indonesia

Claudio Contreras / Finespotted Jawfish (Opistognathus punctatus), Bahia Magdalena, Baja California Peninsula, Mexico, June

Tony Wu / Jawfish (Opistognathus sp) looking around after spitting out sand and rubble to maintain burrow. Lembeh Strait, Celebes Sea, North Sulawesi, Indonesia.

Tony Wu / Jawfish (Opistognathus sp.) spitting out sand and stones to maintain its burrow. Lembeh Strait, Celebes Sea, North Sulawesi, Indonesia.

Tony Wu / Jawfish (Opistognathus sp.) spitting out sand and stones to maintain its burrow. Lembeh Strait, Celebes Sea, North Sulawesi, Indonesia.

Alex Mustard / Yellowhead jawfish (Opistognathus aurifrons) male churning / aerating eggs by spitting them out of his mouth. East End, Grand Cayman, Cayman Islands, British West Indies. Caribbean Sea.

Alex Mustard / Variable jawfish (Opistognathus variabilis) emerging from its hole in the sea bed, close to a coral reef. Ambon Bay, Ambon, Maluku Archipelago, Indonesia. Banda Sea, tropical west Pacific Ocean.

Alex Mustard / Yellowhead jawfish (Opistognathus aurifrons) male aerating his eggs by spitting them out of his mouth, a behaviour known as churning. These are new eggs and have not yet developed eyes. East End, Gran...

Alex Mustard / Yellowhead jawfish (Opistognathus aurifrons) spitting out sand as it digs its burrow. East End, Grand Cayman, Cayman Islands, British West Indies. Caribbean Sea.