Stomias affinis, also known as Gunther's boafish, is a deep-sea mesopelagic fish species in the family Stomiidae.

They inhabit the open seas in the equatorial zones of the Atlantic, Indian and Pacific Oceans.

Stomias affinis is an elongated, slender, barbeled dragonfish and is a sexually dimorphic species.

[3] The fish's stomach is caramel in color with white spots and constitutes seventy-five percent of the total body length.

They share the same habitat area as Stomias nebuloses and are not suited for living in a low-oxygen environment.