Spotted Blue Eye, Pseudomugil gertrudae Weber 1911

Other Names: Gertrude's Blue Eye, Gertrude's Blue-eye, Northern Blue-eye, Spotted Blue-eye

Summary:

A very small blue eye with a characteristic pattern of black spots on the dorsal, anal and caudal fins.

Cite this page as:

Bray, D.J. & Thompson, V.J. 2024, Pseudomugil gertrudae in Fishes of Australia, accessed 27 Jun 2025, https://fishesofaustralia.net.au/Home/species/4093

Spotted Blue Eye, Pseudomugil gertrudae Weber 1911

More Info

Distribution	Isolated populations in the Northern Territory and northern Queensland, from the Finniss River and Groote Eylandt, Northern Territory, and the Jardine River system, several small creeks at the tip of Cape York Peninsula, and the Murray Swamps near Tully, Queensland. Elsewhere the species occurs in West Papua, Indonesia, and Papua New Guinea. Found in a range of freshwater habitats including small sandy or muddy-bottomed creeks, swamps and marshes, shady rainforest streams, lily lagoons, backwaters and overflows adjacent to larger rivers. Commonly aggregates in areas with abundant vegetation and woody debris.
Features	Dorsal fin IV-VI + 6-8; Anal fin 9-12; Pectoral fin 8-11. Body relatively elongate, laterally compressed; greatest body depth 21.9-25.5% SL; head length 24.2-28.1; snout length 4.0-5.4; eye diameter 8.5-10.3; mouth small with a protractile maxillary, gape greatly restricted by labial ligament; jaw teeth conical to caniniform, moderately large, strongly curved backwards; with or without one or more rows of teeth extending outside of mouth; vomer and palatines toothless. Scales cycloid with well-developed radii; horizontal scale rows 6 or 7; vertical scale rows 25 to 28; cheek with 3-5 scales. Two separate dorsal fins; first dorsal fin originating under tip of pectoral; anal fin originating under end of first dorsal and in front of second dorsal origin; dorsal and anal fins lack rigid spines; pectoral fins short and set in a horizontal plane; mature males with elongate anterior dorsal, anal, and pelvic fin rays.
Size	To 3.8 cm SL.
Colour	Body silvery white to almost transparent to a pale tannish-yellow with a network of dark scale outlines, 3 horizontal black lines on the rear of the body, distinctive black spotting on the pale yellow median fins, and a blue eye. Males are usually more intensely spotted than females, and the first dorsal fin is usually yellow.
Feeding	Feeds mostly on micro-crustaceans and insect larvae.
Biology	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 are small and adhesive. Larvae hatch in 2-3 weeks; small at hatching (3.8-4.0 mm SL) but eyes and swim bladder are well developed and body is well pigmented.
Fisheries	A popular aquarium fish.
Conservation	IUCN: Least Concern
Remarks	Populations are considerably variable in colour, fin shape and size.
Etymology	The species was named in honour of Gertrude Merton, who accompanied her husband Dr Hugo Merton, a German naturalist, who travelled throughout the Aru Islands - the type locality.
Species Citation	Pseudomugil gertrudae Weber, 1911, Abh. Senckenb. Naturforsch. Ges. 34: 23. Type locality: Ngaiguli, Terangan, Aru lslands (lectotype)
Author	Bray, D.J. & Thompson, V.J. 2024
Resources	Atlas of Living Australia Australian Faunal Directory Catalog of Fishes

Spotted Blue Eye, Pseudomugil gertrudae Weber 1911

References

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Allen, G.R. 1991. Field guide to the freshwater fishes of New Guinea. Christensen Research Institute, Madang, Papua New Guinea.

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

Allen, G.R., Midgley, S.H. & Allen, M. 2002. Field Guide to the Freshwater Fishes of Australia. Perth : Western Australian Museum 394 pp.

Allen, G.R., Unmack, P.J. & Hadiaty, R.K. 2016. Pseudomugil luminatus, a new species of Blue-eye (Teleostei: Pseudomugilidae) from southern New Guinea, with notes on P. gertrudae. Fishes of Sahul 30 (1): 950-961.

Cook, B.D., Unmack, P.J., Huey, J.A. & Hughes, J.M. 2014. Origin of relict populations of freshwater fishes in northern Australia with common disjunct distributions (Pseudomugil gertrudae, Denariusa australis and Melanotaenia maccullochi). Freshwater Science 33: 263–272.

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Hitchcock, G., Finn, M.A., Burrows, D.W., & Johnson, J.W. 2012. Fishes from fresh and brackish waters of islands in Torres Strait, far north Queensland. Memoirs of the Queensland Museum 56(1): 14-24

Howe, E. 1987. Breeding behaviour, egg surface morphology and embryonic development in four Australian species of the genus Pseudomugil (Pisces : Melanotaeniidae). Marine and Freshwater Research 38(6): 885-895

Larson, H.K. & Martin, K.C. 1990. Freshwater Fishes of the Northern Territory. Northern Territory Museum of Arts and Sciences Handbook Series Number 1. Darwin : Northern Territory Museum of Arts and Sciences 102 pp. 73 figs.

Larson, H.K., Williams, R.S. & Hammer, M.P. 2013. An annotated checklist of the fishes of the Northern Territory, Australia. Zootaxa 3696(1): 1-293

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Merrick, J.R. & Schmida, G.E. 1984. Australian Freshwater Fishes Biology and Management. Sydney : J.R. Merrick 409 pp. figs 280 col. figs.

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Pusey, B.J., Kennard, M.J. & Bird, J. 2000. Fishes of the dune fields of Cape Flattery, northern Queensland and other dune systems in north-eastern Australia. Ichthyological Explorations of Freshwater 11(1): 65-74

Nijssen, H., van Tuijl, L. & Isbrücker, J.H. 1982. A catalogue of the type-specimens of Recent fishes in the Institute of Taxonomic Zoology (Zoölogisch Museum), University of Amsterdam, The Netherlands. Verhandelingen van het Bataviaasch Genootschap van Kunsten en Wetenschappen 33: 1-173 (lectotype designation)

Saeed, B., Ivantsoff, W. & Allen, G.R. 1989. Taxonomic revision of the family Pseudomugilidae (Order Atheriniformes). Australian Journal of Marine and Freshwater Research 40: 719-787

Weber, M. 1911. Die Fische der Aru- und Kei-Inseln. Ein Beitrag zur Zoogeographie dieser Inseln. Abhandlungen der Senckenbergischen Naturforschenden Gesellschaft 34: 1-49 figs 1-11