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| Pseudomugil gertrudae [Weipa] - photo© Günther Schmida |
Weber, 1911
Spotted Blue-eye
Description
Pseudomugil gertrudae has a moderately compressed and elongated body, up to 30 mm SL. The body colouration is translucent green to silvery with diffused reddish spot between eye and pectoral fin. The tips of the pectoral fins can be bright yellow, orange or orange-red, other fins often edged with white. The dorsal, anal and tail fins can be either white or yellow with rounded or oblong dark spots scattered all over. Black spots on scales on side of body forming several rows. Two dorsal fins, very close together, the first much smaller than the second. Males have elongated dorsal, anal and pelvic fins and more spots than females. This species has a very wide distribution and as such is available in a variety of different coloured forms and variable fin shapes. Pseudomugil gertrudae is closely related to Pseudomugil paskai; both species are characterised by rows of permanent spots covering the fins. They were named "gertrudae" after the wife of Dr. Hugo Merton, a scientist who visited the Aru Islands.
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| Pseudomugil gertrudae [Bathurst Island] - photo© Neil Armstrong |
Distribution & Habitat
Pseudomugil gertrudae were originally collected from the Aru Islands, which lies directly south of the Vogelkop Peninsula, West Papua. This species is widely distributed in scattered localities throughout the Northern Territory, northern Queensland, and south-western New Guinea. In New Guinea it has mainly been collected from Pahoturi, lower Fly, and Bensbach river systems, but no doubt ranges westward into southern West Papua.
Pseudomugil gertrudae are found in small creeks, lagoons, billabongs, swamps and rainforest streams, often associated with dense aquatic vegetation. Habitat conditions vary substantially but they are usually found in fairly soft waters with a temperature range of 23-30°C, and pH 5.2-7.6. Spawning usually occurs from October to December.
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| Pseudomugil gertrudae [Jardine River] - photo© Neil Armstrong |
Keeping & Caring
Pseudomugil gertrudae are a very attractive species and well-suited to the smaller aquarium. When maintained in a small group the males will regularly display to each other and they look like small colourful butterflies as they dart among the spawning medium. A small 50 litre aquarium, decorated with floating water sprite, driftwood overgrown with Java moss and containing a small group of mixed males and females will delight the eyes of the most discerning hobbyist. This species has a very wide distribution and as such is available in a variety of different coloured forms and variable fin shapes. My favourites are the varieties from the Jardine River and the Kakadu Wetlands.
I obtain my first specimens in 1980 and maintained a small population until 1995. I successfully bred and raised the fry under the following water conditions : Temperature 19-31°C, pH 6.4-8.2, Alkalinity 10-50 ppm (mg/l), and General Hardness 100-170 ppm (mg/l).
Pseudomugil gertrudae have a generalised diet in their natural habitat consuming aquatic prey items such as small crustaceans, daphnia, various aquatic insects, other aquatic invertebrates, algae, diatoms and small quantities of terrestrial insects such as flies. In captivity, they can be fed live or frozen foods such as daphnia, copepods, mosquito larvae or brine shrimp. Whiteworms and other small worms are also an excellent food. Flake food or small bite-sized pellets can also be fed with success however for best results some supplementary feeding with live or frozen food is required.
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| Pseudomugil gertrudae [Cadell River, NT] - photo© Dave Wilson |
Breeding this species is generally uncomplicated. Males display with their dorsal and anal fins raised while actively pursuing a female. During this spawning procedure the colour of the fins intensifies and the spots on the body becoming very dark. Spawning often continues throughout the day, with each female releasing up to 10 or 12 eggs. The eggs are transparent and are relatively large (1 mm), and depending on water temperature, will hatch in 9 to 11 days. Upon hatching the fry will be seen swimming at the surface of the water and can be fed newly-hatched brine shrimp, microworm or finely powdered dry foods. At around six months of age if adequately fed, they should be about 20-25 mm long.
© Copyright Adrian R. Tappin
Updated February, 2007.
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