The Jawfish – Opistognathidae – is a large family of about 80 species of small, tropical fish belonging to the order of Perciformes. They live in the warm, shallow waters of the Indian, Pacific and Atlantic Ocean. They prefer living in burrows that they build themselves or in small cavities in the sand, the maximum depth of their habitat not exceeding a few dozen meters.
The Physical Features of the Jawfish (Opistognathidae)
The species belonging to the family of Opistognathidae are all small, usually not larger than 10 cm (with the only exception of the Giant variety, which usually reaches about 50 cm). They have disproportionally large heads and jaws (hence the name) used not only for feeding, but for holding their young and for building their burrows as well. Most of them are colorful, brown, blue, green and yellow being the most frequently encountered colors. Other distinctive features of jawfish (Opistognathidae) include the long undivided dorsal fin( which consists of about a dozen spines), a rounded or pointed caudal fin, and the spine consisting of five soft rays, out of which three are branched and weak and two are hard and have no branches. They are scaly, but their head is free from scales.
Lifestyle and Behavioral Characteristics of Opistognathidae
These little creatures are territorial, living in colonies consisting of burrows only a few feet apart from each other. They either build their own burrows or they use the abandoned burrows of other small marine creatures, such as tubeworms, and they are constantly cleaning their home, sweeping out the sand or other debris that is pushed into the cave by currents. They are quite reclusive, though, spending most of their time inside their burrows, looking out from their hiding place to see whether there is any food swimming around.
Jawfishes – Basic Aspects Regarding Diet and Breeding
Jawfishes are predators, hiding in their caves and snatching the small crustaceans, fish and invertebrates that pass by. However, their large mouths have developed not only for satisfying their huge appetite – jawfishes also use their mouth to provide home for their fertilized eggs until they hatch. Courtship takes place in summer, usually at dusk. The eggs are spawn in a cave, then the father – not the mother! – harbors the fertilized eggs in his mouth, releasing the young into the free water after hatching. The free-swimming young jawfish (Opistognathidae) then needs only about two weeks to develop sufficiently for building its own burrow.