Animal Species:Pacific Blue Eye, Pseudomugil signifer Kner, 1865

The Pacific Blue Eye is an Australian native fish that, as its common name suggests, has blue eyes.

Standard Common Name

Pacific Blue Eye

Alternative Name/s

Blue-eye, Northern Blue-eye, Southern Blue-eye


The Pacific Blue Eye has a semi-transparent body that can vary in colour from pale olive, yellow to bluish. As the common name suggests, the iris of the Pacific Blue Eye is blue. The operculum and belly region are silvery. There is often a series of pearly spots along the side of the body.

The fins of males and females are different shapes. The dorsal, anal and pelvic fins of males are extended into filaments. The fins can also differ in colouration, particularly during breeding when the fins of the male can become brilliantly coloured.

Size range

Males grow to 88 mm in length and females grow to 63 mm.


It is an Australian native species that occurs in coastal streams along the eastern coast of Australia from northern Queensland to southern New South Wales.

The map below shows the Australian distribution of the species based on public sightings and specimens in Australian Museums.  Source: Atlas of Living Australia.

Pseudomugil signifer

Distribution by collection data

Ozcam map of Pacific Blue Eye specimens in the Australian Museums.

What does this mean?


The Pacific Blue Eye lives in clear, fast flowing streams and also in mangrove regions of estuaries.

Habitat type

Freshwater Habitat: freshwater

What does this mean?

Feeding and Diet

The species feeds on mosquito larvae and other insects.

Life cycle

Females lay one or two eggs at each spawning with up to nine spawnings a day over the spawning period, which may last over a week.  The 1.8 mm diameter eggs attach to vegetation by adhesive filaments.  At 220C to 240C the eggs take 18 to 21 days to develop.  Well developed young hatch and can feed immediately.  In an aquarium, the newly hatched young can reach maturity in six months.

Mating and reproduction

At courtship a male will dart backwards and forwards in front of the female, while fluttering the pectoral fins and holding the dorsal, anal and pelvic fins erect. At spawning, the two fish swim into vegetation and their bodies shake violently. 



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  1. Allen, G.R. 1989. Freshwater Fishes of Australia. T.F.H. Publications. Pp. 240.
  2. Ivantsoff, W & L.E.L.M. Crowley in McDowall, R.M. 1996. Freshwater Fishes of South-Eastern Australia. Reed Books. Pp. 247.
  3. Merrick, J.R. & G.E. Schmida. 1984. Australian Freshwater Fishes. Biology and Management. John R. Merrick. Pp. 409.

Mark McGrouther , Senior Fellow
Last Updated:

Tags fishes, ichthyology, Pacific Blue Eye, Pseudomugil signifer, Pseudomugilidae, Australian native, blue eyes, Blue-eye, Northern Blue-eye, Southern Blue-eye, semi-transparent, pale olive, yellow, blue, silvery belly, 30 cm - 1 m, coastal streams, fast-flowing streams, mangrove, freshwater,


Mark McGrouther - 9.04 AM, 14 April 2010

Hi Paris,  Thank you for your comment.  I have added some extra information to the page that may be of interest to you.  It sounds to me as though you are doing everying right.  I can't add much except perhaps refer you to a site that contains additional information on breeding of Pacific Blue-eyes.  You may wish to look at the Aquatic Community page for the species at  Please let me know how things progress.  You may wish to write another comment about your progress.  Best of luck!

pacific blue eye breeder - 6.04 PM, 13 April 2010
Hi, I am currently working with Pacific Blue eyes in a school aquarium for science. It has been around 10 weeks that I have had to provide 5 blue eyes with their natural habitats, good comforting food and at the same time try and breed them Two of the fish are males and three are females- is this a good enough ratio between the genders? I have been trying to breed them since day 1, however my team members and I have only seen small progress. We have done the following though, and Im asking whether you could offer me with any other different alternatives or solutions to have a succesful breeding. Since mid-february I have: 1. done regular water changes of about 20-30% of a 60 litre tank. 2. fed them with a variety of food including quality flake food, blood worms and brine shrimp- they tend to enjoy eating the bloodworms most. 3. Provided them with a spawning mop 4. change the light settings so that they get light during the day and darkness throughout the night 5. the tank is near a window, but it is not so near that there is direct sunlight 6. I have made sure to keep the nitrate levels between 7-8, and the ph level under 20 7. I have added valve, and eloda weed as the plants 8. lots of rocks for hiding places Is there anything that I could include in what Im already doing, or can I change anything that I am currently doing to the aqaurium do you think? Since they first arrived in the tank the pacific blue eyes have turned from semi-transparent to a silvery - grey colour. I know that when their colours get stronger they are more likely to breed, is this true? Well, thank you for your time. If you have any information regarding successful breeding of pacific blue eye, that would be gladly appreciated :-) Thank you

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