The coloration of this species is variable. It is often brown or green with pale stripes and bars, and white spots posteriorly. A yellow (or xanthic) color variety is common in some areas. Individual fish have the ability to change their colors very quickly.

This species grows to 80 cm in length.

The Trumpetfish uses stealth and camouflage to prey on small fishes. It often approaches its prey vertically, darting down from above and sucking the prey into its long snout.

It is known to sometimes follow other fishes. Presumably following herbivorous fishes such as the Blue-lined Spinefoot allows the Trumpetfish to more easily approach potential prey without detection.

There is only one species in the genus Aulostomus. It occurs on coral reefs throughout the Indo-Pacific and eastern Pacific.