E-Fauna BC: Electronic Atlas of the Wildlife of British Columbia

Diaphus theta Eigenmann & Eigenmann, 1890
California Headlightfish
Family: Myctophidae
Photo of species

© Aaron Baldwin  Email the photographer   (Photo ID #18411)

Source: Distribution of Diaphus theta as compiled by Aquamaps
E-Fauna's interactive maps for fish are not yet available.


This is a species of lanternfish that is found in the Eastern Pacific. Lanternfish are small deep sea fish that have rows of photophores along each side and use bioluminescence. This species exhibits daily vertical migration for feeding.

Species Information

Dorsal spines (total): 0; Dorsal soft rays (total): 12 - 14; Anal spines: 0; Anal soft rays: 12 - 14; Vertebrae: 34 - 36. Adipose small, narrow based, slender (Ref. 6885). Brown to black on dorsal surface, lighter ventrally; fins pale (Ref. 6885). Branchiostegal rays: 9 (Ref. 31442).

Source: FishBase. Clemens, W.A. and G.V Wilby. 1961 . (Ref. 4925).


Species Biology

Epipelagic to mesopelagic (Ref. 31442). Feed at night or in the morning (Ref. 9199), on euphausiids, copepods, and amphipods (Ref. 11712). Oviparous, with planktonic eggs and larvae (Ref. 31442). Lipid content is 15.8 % in fresh body weight while wax ester is present in trace amounts (Ref. 9197). Minimum depth reported from Ref. 6885. bathypelagic; marine; depth range 0 - 3400 m (Ref. 50550), usually 10 - 400 m (Ref. 28981). Deep water.

Source: FishBase. Clemens, W.A. and G.V Wilby. 1961 . (Ref. 4925).



Eastern Pacific: common in California Current region to 20°S (Ref. 31442), including Hawaii (Ref. 4925). Northwest Pacific: throughout subarctic-transitional waters to northern Japan (Ref. 31442).

Source: FishBase. Clemens, W.A. and G.V Wilby. 1961 . (Ref. 4925).

Status Information

Origin StatusProvincial StatusBC List
(Red Blue List)
NativeSNRNo StatusNot Listed
BC Ministry of Environment: BC Species and Ecosystems Explorer--the authoritative source for conservation information in British Columbia.

Additional Range and Status Information Links

Additional Photo Sources

General References

Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2021. E-Fauna BC: Electronic Atlas of the Fauna of British Columbia [efauna.bc.ca]. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. [Accessed: 2024-04-22 8:18:18 AM]
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