Common name: Deepsea Smelts, Smallmouths, Pencil smelts
A family of small to medium-sized generally deepwater fishes; divided into two subfamilies: Bathylaginae and Microstomatinae.

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Cite this page as:
Bray, D.J. 2018, Pencil smelts, MICROSTOMATIDAE in Fishes of Australia, accessed 20 Jul 2024,

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Family Taxonomy

The family comprises 11 genera with about 38 species. Eight genera with 9 described species are known from Australian waters.

Family Distribution

Although microstomatids occur worldwide in all oceans from tropical to polar latitudes, they are most common in cooler waters. They are deepwater meso-, bathy-, and possibly benthopelagic fishes that probably migrate vertically. Some species are epipelagic to within 100 m of surface at night.

Family Description

Slender, elongate to very elongate, delicate, soft-bodied fishes, head small to moderate, eyes moderate to large, either lateral, or tubular and directed anteriorly; snout short, often blunt, much less than eye diameter, mouth small, premaxilla present, tiny teeth in lower jaw, absent from upper jaw. Single, short-based dorsal and anal fins, pectoral fins usually small, on mid-side or close to ventral edge of body, pelvic fins small, abdominal, dorsal adipose fin present or absent, caudal fin forked. Scales cycloid, deciduous, lateral line when present running straight along midline of body, extending onto tail in some. Light organs and luminous tissue absent; swim bladder absent.

Family Size

Microstomatids reach a length of 25 cm.

Family Feeding

Pelagic carnivores feeding on zooplankton.

Family Reproduction

Reproduction is oviparous. The pelagic eggs are small and larval development to metamorphosed juvenile is gradual.

Family Commercial

Although microstomatids are of no commercial importance, they are an important source of food for larger pelagic fishes.


Bray, D.J. 2018

References - larval development

Ahlstrom, E.H., Moser, H.G. & Cohen, D.M. 1984. Argentinoidei: development and relationships. Pp. 155-169, In Moser, H.G., W.J. Richards, D.M. Cohen, M.P. Fahay, A.W. Kendall, Jr. & S.L. Richardson (eds.), Ontogeny and Systematics of Fishes, Spec. Publ. No. 1, Amer. Soc. Ichthy. Herpet. ix + 760 pp.

Begle, D.P. 1992. Monophyly and relationships of argentinoid fishes. Copeia 1992(2): 350-366.

Johnson, G.D. & Patterson, C. 1996. Relationships of lower euteleostean fishes. Pp. 251-332 In Stiassny, M.L.J., Parenti, L.R. & Johnson, G.D. (eds) Interrelationships of fishes. San Diego: Academic Press, 496 pp.

Kawaguchi, K. & Butler, J.L. 1984. Fishes of the genus Nansenia (Microstomatidae) with descriptions of seven new species. Los Angeles Co. Mus. Nat. Hist. Contrib. Sci. 352: 1-22.

Kobyliansky, S.G. 1990. Taxonomic status of microstomatid fishes and problems of classification of suborder Argentinoidei (Salmoniformes, Teleostei). Tr. Inst. Okeanol. Akad. Nauk SSSR 125: 147-177. [In Russian.]

Paxton, J.R. & D.M. Cohen. 1999. Families Argentinidae, Microstomatidae, Bathylagidae, and Opisthoproctidae. In Carpenter, K.E. & V.H. Niem. Species identification guide for fisheries purposes. The living marine resources of the western central Pacific. Batoid fishes, chimeras and bony fishes. Part 1 (Elopidae to Linophrynidae). FAO, Rome.

Paxton, J. R. , J. E. Gates, D. J. Bray & D. F. Hoese.  2006. Family Microstomatidae, In Hoese, D.F., D.J. Bray, G.R. Allen, J.R. Paxton, Beesley, P.L. & A. Wells. Zoological Catalogue of Australia Volume 35, Fishes. Parts 1 – 3. CSIRO PUBLISHING / Australian Biological Resources Study (ABRS). 2248 pp.