Yellowheaded Jawfish, Opistognathus aurifrons
Click for closer view of jawfish
A variety of different species of jawfish are widespread in coral reefs areas around the world. Yellowheaded jawfish are one of several jawfish species from the Caribbean and the Florida Keys, where they live in sandy areas adjacent to coral reefs.
Yellowheaded jawfish are very industrious diggers of burrows, which they reinforce using pebbles. In an aquarium, they can frequently be observed working on their burrows, shoveling out mouthfuls of sand and stealing pebbles from their neighbors. The fish expend a tremendous amount of energy building these burrows. Initially, it seems their burrows are continually collapsing, but after days (or sometimes weeks) of work, the burrows become quite stable.
Yellowheaded jawfish seldom stray far from the protection of their burrows, spending most of their time hovering at the mouths of their burrows waiting to snatch passing plankton. In the evening they retreat into their burrows for the night, using several large pebbles to cover the burrow opening to conceal it from nighttime predators.
Normally only one jawfish lives in each burrow, and individuals vigorously defend their burrows from other fish. In aquaria sometimes dominant individuals will move to the burrows of other jawfish, generally kicking out the original tenant.
Jawfish do visit each other's burrows for breeding, however, since spawning takes place within the burrows. Male jawfish carry the eggs in their mouths untill they hatch.