Small fishes (14-30 cm); body elongate, extremely compressed, bladelike with a sharp ventral edge; thin, transparent bony casing entirely cover the body. Head elongate, snout long, slender, and tubular; mouth small, toothless. First dorsal spine long and sharp, located at the hindmost end of body; dorsal and caudal soft fins are displaced ventrally. Lateral line absent. Color: variable with the species, either silvery or yellowish brown to pale green on back, silvery on sides; dusky to conspicuous lateral streak running through eye.|
Similar families occurring in the area. Macrorhamphosidae: body not blade-like, lacking bony casing, with small but distinct scales; first dorsalfin originating near midbody; second dorsal-fin spine greatly enlarged, serrated on posterior edge; caudal not on ventral surface of body. Solenostomidae: body not blade-like, covered with stellate plates that bear spines; pelvic fin enlarged; caudal not on ventral surface of body.
Remarks. Found on muddy bottom near mangroves to inshore coral reefs; swim in vertical position with the snout downwards, frequently seeking refuge among coral branches or the spines of long-spined sea urchins; feed on small benthic invertebrates and zooplankton.