The longfin smooth-head (Conocara macropterum) is a species of fish in the family Alepocephalidae.
The longfin smooth-head is pale brown to black in colour; its name derives from its anal fin, which has a long base and 35âÂÂ39 finrays. Its maximum length is . They grow rapidly from infancy; few juveniles of intermediate size are found.
The longfin smooth-head lives in the temperate and tropical Atlantic Ocean, and in the Gulf of Mexico; it is bathypelagic, living at depths of , being most common at .
The longfin smooth-head lays large eggs, up to in diameter, and are believed to be buried in redds, similar to how the Atlantic salmon buries its eggs. A detritivore, the longfin smooth-head is recorded to ingest sediment from the seafloor, taking up with it microfauna such as foraminiferans.