The family Aulostomidae is a monogeneric family of highly-specialized, tubularly-elongated marine fishes commonly known as trumpetfishes. Aulostomids belong to the order Syngnathiformes, along with the popular seahorses and the similarly-built cornetfishes. The family's sole genus, Aulostomus, has three distinct species.
Trumpetfishes are found in tropical waters worldwide, with two species in the Atlantic and one in the Indo-Pacific. They are mostly demersal reef-dwellers, although one of the species seems to prefer rocky substrata.
They are relatively large for reef fish, reaching almost up to a meter in length. Their bodies are elongated and rigid, often cigar-shaped. The dorsal and anal fins are set well back, almost adjacent to the tail, although there are individual dorsal spines reaching midway towards the head region. Like most members of the order Syngnathiformes, their bodies are inflexible, supported by interwoven struts of bone. One of the family's most distinct traits is the long, tubular snout ending in somewhat nondescript jaws. Members of the family have the capability to rapidly expand their jaws into a circular gaping hole almost the diameter of their body when feeding.
Aulostomids are highly carnivorous fish. They hover, almost-motionless just a few inches above the substrate, slowly inching their way towards unsuspecting prey. When they get close enough, they rapidly dart in, expanding their jaws. The rapid opening of their tube-like mouths creates a strong sucking force, drawing their prey straight into their oral cavities. Aulostomidae are known to feed almost exclusively on small, schooling reef fishes.
While they have no commercial fisheries value, members of the family have been known to occasionally be found in the aquarium trade. Not popular aquarium fish, they are common enough in the hobby that some websites have instructions on keeping them in captivity.
The name of the family Aulostomidae is derived from the only genus in the family, Aulostomus. The name is a composite of two Greek words: "aulos", meaning flute and "stoma" which is Greek for mouth. This refers to the odd appearance of their tubular snouts. In fact, "flutemouth" is another less-common name for the members of the family (although this moniker is more often used to refer to the closely-related cornetfishes of the family Fistulariidae.