[3] Like other members of the subfamily Sternoptychinae, Argyropelecus olfersii has a laterally compressed and extremely deep body, contributing to the characteristic "hatchet" shape which the group is named after.

This shape, alongside the counterillumination provided by the well-developed ventral photophores, reduces the silhouette of the fish when viewed from beneath, concealing it from potential predators.

[4] A. olfersii has a dark, heavily pigmented back and silvered flanks, again helping to reduce visibility in its native midwater habitat.

Like all members of the genus Argyropelecus, A. olfersii has dorsally-directed, tubular eyes, which in life have a metallic blue colouration that is rapidly lost in preserved specimens.

[3] Despite being an abundant member of the mesopelagic community, A. olfersii is a relatively poor source of energy, and there is evidence suggesting that it is actively avoided by some marine mammal predators in favour of more energy-rich myctophids.