Females are known as flabby whalefishes, Males are known as bignose fishes, while juveniles are known as tapetails and were formerly thought to be in a separate family, dubbed Mirapinnidae.

Living at extreme, lightless depths, adult females have evolved an exceptionally well-developed lateral line system.

Their eyes are either very small or vestigial and instead this system of sensory pores (running the length of the body in a distinct lateral line) helps the fish to accurately perceive its surroundings by detecting vibrations.

Apparently, "morphological transformations involve dramatic changes in the skeleton, most spectacularly in the head, and are correlated with distinctly different feeding mechanisms.

Females have huge gapes with long, horizontal jaws and specialized gill arches allowing them to capture larger prey.

"[1] Like many deep-sea fishes, Cetomimidae is thought to undergo nightly vertical migrations; they feed within the upper 700 m of the water column by starlight and retreat back to the abyssal depths by daybreak.

Before a report released in January 2009, the juveniles of the species were thought to belong to a separate taxonomic family Mirapinnidae in the Cetomimiform order, with three genera Eutaeniophorus, Mirapinna, and Parataeniophorus.