Sigmops bathyphilus, commonly called the spark anglemouth, deepsea fangjaw or deepsea lightfish,[3] is a species of fish in the family Gonostomatidae (anglemouths).

[4] Sigmops bathyphilus is black in colour, with a maximum length of 20 cm (7.9 in) for the female and 15 cm (5.9 in) for the male.

[8] It is bathypelagic, living at depths of 700–3,000 m (2,300–9,800 ft), hence its specific name, from Greek words meaning "depth-loving".

[5][9] Sigmops bathyphilus undergoes sex reversal (from male to female) at a length of 5–10 cm (2.0–3.9 in), with females spawning once they reach 11 cm (4.3 in).

Some individuals are "super males", who do not change sex and are the principal spawners.