[3] The longsnout butterflyfish was first described in 1860 by Felipe Poey y Aloy and Albert C. L. G. Günther in two separate reports.

[4][5] Between them the fish was given three separate scientific names each one in a different genus, though Poey's assignment of the species to Prognathodes is the only valid combination.

[7] The upper half of the longsnout butterflyfish is yellow that changes to orange and again darkens to brownish-orange.

[7] Fairly common throughout its range, the longsnout butterflyfish is found on natural and artificial reefs, usually 30 to 200 ft (10–60 m) in depth.

[2][9] Unlike many other members of its family, the longsnout butterflyfish does not pick parasites from other fish.