Family Gonostomatidae

Common names:  Bristlemouths

Distribution:  Worldwide in the mesopelagic and bathypelagic zones.

General description and features:  Typically very small elongate fishes with rows of small photophores on their bellies.  Mouth large with many small teeth, and usually fine gill rakers

Feeding:  Very diverse.  Small genera such as Cyclothone feed primarily on small crustaceans such as copepods and larger genera such as Gonostoma may feed on small fish and larger crustaceans.  Ichthyococcus feeds on gelatinous organisms such as small medusa and salps.

Reproduction and life history:  Gonostomatids are the most abundant fish in the world not because they are particularly abundant in any one location but because they are found in all the worlds oceans in the mesopelagic realm.  Their success may be explained by their numerous teeth and fine gill rakers, which enables them to feed on large prey and plankton which they migrate to the surface to feed upon at night. Males have strong olfactory abilities suggesting mate location similar to the hatchetfishes.

Gonostoma sp. collected from the central North Pacific (Photo by J. Drazen).

Cyclothone sp. from the Catalina Channel, California (photo by J. Drazen) and photographed in Monterey Bay.

Ichthyococcus sp. from the Catalina Channel, California (photo by J. Drazen). Its pug nose has earned it the name "bulldog lightfish."  This fish feeds on gelatinous animals such as salps and medusa.  It has a very elongate gut for processing this type of food and its pug nose, very unusual in this group, may also be an adaptation for feeding on these types of animals.  This fish is sometimes placed in another related family Photoichthyidae.