Pacific Blue Eye, Pseudomugil signifer Kner 1867

Other Names: Blue Eye, Blue-eye, Island Blue-eye, Northern Blue Eye, Northern Blue-eye, Pacific Blue-eye, Southern Blue-eye

Pacific Blue Eyes, Pseudomugil signifer, in Carrolls Creek, Roseville, New South Wales, January 2017. Source: Greg Wallis / License: CC BY Attribution-NonCommercial

The Pacific Blue Eye is a relatively large, common species that displays a wide range of morphological variation among geographic areas. This species is found along the Queensland and New South Wales coast and tolerates a wide range of salinities from fresh water to sea water. A distinctive long-finned variety occurs in coastal north Queensland.

Cite this page as:
Vanessa J. Thompson, Pseudomugil signifer in Fishes of Australia, accessed 23 May 2022,

Pacific Blue Eye, Pseudomugil signifer Kner 1867

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Widely distributed along the east coast of Queensland and New South Wales. Found in streams and estuaries from Weipa, Gulf of Carpentaria, QLD (141º53´E) to Narooma, NSW (36º15´S), also some offshore islands of QLD including Lizard Is. (14º40´S), Low Isles (16º23´S) and Fraser Is. (25º22´S). Tropical, inhabiting a variety of habitats from marine to freshwater. Generally in tidal mangrove creeks or fringing coastal mangrove, around offshore islands and also in clear forest streams. Forms loose schools of hundreds to thousands of individuals.


D1 III-VI (rays); D2 7-11; A 10-13; P 9-14; V 5; C 15

Body relatively elongate, laterally compressed; greatest body depth 23.3-30.4 in SL; head length 26.3-28.4; snout length 6.1-8.0; mouth subvertical and small with a protractile maxillary; jaw teeth conical to caniniform, posterior premaixillary teeth enlarged and exposed when mouth closed; with or without one or more rows extending outside of mouth; vomer and palatines toothless; eye relatively large, eye diameter 9.0-10.5; mandibular pores present; head pores large.

Scales relatively large, cycloid with well-developed radii; horizontal scale rows 6; vertical scale rows 26 to 30; cheek with few scales;

Two separate dorsal fins; dorsal and anal fins lack rigid spines; first dorsal originating before tip of pectoral about midway along body; anal originating under end or just behind first dorsal and in front of second dorsal origin; pectoral fins pointed, short and set in a horizontal plane; males with elongate anterior dorsal, anal and ventral fin rays; caudal fin forked with rounded tips.


To 7cm SL, commonly to 4 cm.


Eye blue; body and fin colouration varies from semi-transparent yellowish-tan to silvery blue-grey with dark scale outlines; often with a row of long white spots across mid-line; irridescent mid lateral spots often present; fins clear to yellow-orange; males with black blotches at base of anal and second dorsal fins which may also have a white edge; males color intensifies during breeding.


Feed mainly on micro-crustaceans and insect larvae.


Breed opportunistically throughout the year. Males display to females by intensifying their colours and erecting their ornate fins. Breeding episodes last several days with females depositing 4-10 adhesive eggs per day amongst aquatic vegetation. Eggs have adhesive filaments and are around 1.8mm in diameter.   Larvae hatch in 2-3 weeks at 22ºC to 24ºC. Larvae are well developed at hatching and are capable of feeding immediately. Often observed in aggregations of tens to hundreds of individuals.


Used as an aquarium species.


Not listed under the IUCN Red List of Threatened Species.
Not listed under the Australian EPBC Act.


Pseudomugil signifier exhibits a wide range of morphological forms with at least 15 geographical varieties recognised. The fins of males and females also differ in shape and colour, particularly during breeding. The dorsal, anal and pelvic fins of males only are extended into filaments and become more intensely coloured during breeding.

Similar Species

Pseudomugil signifier is similar to P. mellis but differs in having larger scales on the nape, larger cephalic sensory pores, and the dorsal, anal and caudal fins of males are generally yellow with a black edge compared to black banded with a white edge in P. mellis.


Generic name Pseudomugil comes from the Greek pseudes meaning false and the Latin mugil meaning a fish, most likely a Mullet. Species name signifier is derived from the Latin signum meaning flag in reference to the elongated dorsal and anal fins of males.

Species Citation

Pseudomugil signifer Kner, R. (1867). Fische, Dritte Abteilung. Reise der österreichischen Fregatte Novara um die Erde in den Jahren 1857–1858–1859, unter den Befehlen des Commodore B. von Wüllestorf-Urbair. Zoologischer Theil 1 (5).  Wien : Kurl Gerold's & Sohn pp. 273–433 pls 12–16 [275]. Sydney, NSW.


Vanessa J. Thompson

Pacific Blue Eye, Pseudomugil signifer Kner 1867


Allen, G.R. (1989). Freshwater Fishes of Australia.  Neptune, New Jersey : T.F.H. Publications pp. 1–240

Allen, G.R. & Cross, N.J. (1982). Rainbowfishes of Australia and Papua-New Guinea.  New Jersey : T.F.H. Publications 142 pp.

Allen, G.R., Midgley, S.H. & Allen, M. (2002). Field guide to the freshwater fishes of Australia.  Perth : Western Australian Museum 394 pp.

Hadfield, A.J., Ivantsoff, V. & Johnston, P.G. (1979). Clinal variation in electrophoretic and morphological characters between two nominal species of the genus Pseudomugil (Pisces: Atheriniformes: Pseudomugilidae). Aust. J. Mar. Freshwat. Res. 30: 375–386 figs 1–4

Leggett, R. & Merrick, J.R. (1987). Australian Native Fishes for Aquariums.  Artarmon : J.R. Merrick Publications 241 pp.

McDowall, R.M. (1996). Freshwater Fishes of South-eastern Australia.  Sydney : Reed Books 2nd Edn  247 pp. [141].

McGlashan, D. J. and Hughes, J.M. (2002) Extensive genetic divergence among populations of the Australian freshwater fish, Pseudomugil signifer (Pseudomugilidae), at different hierarchical scales. Mar. Freshw. Res. 53: 897-907.

Pusey B., Kennard M. & Arthington A. (2004) Freshwater fishes of north-eastern Australia. CSIRO publishing, Collingwood, Victoria 684pp

Saeed, B., Ivantsoff, W. & Allen, G.R. (1989). Taxonomic revision of the family Pseudomugilidae (Order Atheriniformes).  Aust. J. Mar. Freshw. Res. 40: 719–787

Wong, B.B.M., J. S. Keogh and M. D. Jennions (2004) Mate recognition in a freshwater fish: geographical distance, genetic differentiation, and variation in female preference for local over foreign males. J. Evol. Biol. 17(3), 701-708.

Wong, B.B.M., J. S. Keogh and D. J. McGlashan (2004) Current and historical patterns of drainage connectivity in eastern Australia inferred from population genetic structuring in a widespread freshwater fish Pseudomugil signifer (Pseudomugilidae). Molec. Ecol. 13: 391-401

Quick Facts

CAAB Code:37245020


Max Size:7 cm


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