The trumpetfishes are three species of highly specialized, tubularly-elongated marine fishes in the genus Aulostomus, of the monogeneric family Aulostomidae. The trumpetfishes are members of the order Syngnathiformes, together with the seahorses and the similarly built, closely related cornetfishes.

The Syngnathiformes are an order of ray-finned fishes that includes the leafy seadragons, sea moths, trumpetfishes and seahorses, among others.