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| Pseudomugil mellis - photo© Neil Armstrong |
Allen and Ivantsoff, 1982
Honey Blue-eye
Description
Pseudomugil mellis is a small species; usually not exceeding 4 cm. Males are honey-coloured with the first two rays of the dorsal and anal fins black with creamy-brown centres and outer white margins. The female is plain amber with clear fins. The body scales are lightly edged with black. Two dorsal fins, separated by a small gap, the first much smaller than the second. Males are easily distinguished from females by their brighter colours and longer and more elongated dorsal fins. Pseudomugil mellis was formally described by Allen and Ivantsoff in 1982. Before then it was considered to be a colour variety of the Pacific Blue-eye (Pseudomugil signifer). Although, it was always recognised by native fish hobbyists as being different.
Distribution & Habitat
Pseudomugil mellis has a restricted range in southern Queensland, extending northwards from Caboolture to Maryborough, including Fraser Island. It has also been collected in a lake at the northern end of Dismal Swamp, south of Shoalwater Bay. Pseudomugil mellis has been reported from about 18 locations on both the mainland and Fraser Island, although their range had been severely reduced in recent times. It is still relatively abundant in the Noosa River catchment and Fraser Island localities. Most populations are totally isolated from one another. Lacustrine populations occur in seven lakes (six on Fraser Island and one at Cooloola). Pseudomugil mellis is known to co-occur with Pseudomugil signifer at Lake Wabby and Bool Creek on Fraser Island, and Schnapper Creek and Big Tuan Creek on the mainland. Big Tuan Creek is a small coastal creek about 5 km south from the mouth of the Mary River. Although this species is reasonably secure in some areas of its restricted range, its continued existence is being threatened by urban development and the spread of the introduced mosquitofish (Gambusia holbrooki).
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| Typical Honey Blue-eye habitat - photo© Bruce Hansen |
Pseudomugil mellis are usually associated with dystrophic waterbodies of pH 4.4 to 6.8. They can tolerate wide fluctuations in stream temperature, from 14°C in winter to 38°C in summer. Pseudomugil mellis are typically found in the coastal lowland "wallum" country inhabiting freshwater lakes, creeks and wetlands. They are found in both clear and tannin-stained waters with sandy or muddy bottoms. They usually occurs where there is little or no flow and the fish can find shelter within or near to emergent and submerged aquatic macrophytes. Pseudomugil mellis are often found with Rhadinocentrus ornatus, Nannoperca oxleyana, several gudgeons and other small sized native fishes.
Keeping & Caring
I have found this species to not only survive, but breed and prosper in water conditions the exact opposite of that found in the wild e.g. hardness above 150 ppm and pH 7.0. The first time I collected this species from the wild I recorded a water hardness of 10 ppm, pH 5.8, and conductivity 170 µS. I first bred them in 1983 and maintained a small aquarium population until 1994. I obtained additional wild specimens during that time which were added to my aquarium population. I have bred and raised them in captivity with the following water conditions: Temperature 17-28°C, pH 6.8-8.4, General Hardness 90-210 ppm, Alkalinity 10-100 ppm and TDS 170-335. I am sure that you will find that most domestic water supplies that are suitable for human consumption will be adequate for the continual maintenance of this species in captivity. They will display their best colouration when maintained in an aquarium with water that has been stained dark, either by using aquarium peat in the filter or one of the commercial products available for this purpose. A well-planted, partly shaded set-up should also have the same effect. However, this is not required for their successful maintenance in captivity.
Pseudomugil mellis 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. Variety is the spice of life so do not feed them the same foods every day.
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| Pseudomugil mellis [Male - Female] |
Breeding
Studies of captive populations have been well documented and the following summarises much of that information. Males exhibit territorial behaviour guarding the spawning site from intruding conspecifics. Prespawning behaviour is initiated adjacent to the spawning site by the male raising his fins and swimming in a zigzag pattern to block the female's retreat. Spawning usually occurs in late morning and early afternoon with the female entering the spawning site first, followed by the male. After spawning, the male will continue to display, defending his territory and thus the fertilised eggs. Spawning usually commences at around 10-12 months of age when water temperatures exceed 20°C and the fish are about 20 mm in size. Sexual dimorphism is evident, with adult males having larger and more colourful dorsal and anal fins. Males develop black and white fin marking with a golden bronze sheen to the body when displaying.
Females spawn 1-15 eggs each day for about 7-9 days, with 1 to 4 eggs at a time being released amongst aquatic vegetation or synthetic substitutes. After spawning females rest for 4-9 days, during which time they formed schools. Water hardened eggs range from 1.29-1.64 mm in diameter, probably depending on the size of the female and have adhesive tendrils or filaments to attach them to plant material. Eggs hatch 12-14 days (288-336 hours) after fertilisation at a constant water temperature of 24°C. At slightly elevated water temperatures of 25-27°C eggs hatched between 5 and 8 days (112-190 hours). Larvae are around 3.60-5.00 mm SL at hatching and begin feeding at the surface after absorption of the yolk and oil droplets (3-80 hours after hatching).
The small maturation size and the use of batch spawning over successive days were considered to be reasons for the successful recruitment of this species in the wild. Recruitment is further maximised by several mechanisms that decrease predation: territorial defence of the spawning site by the male, direct pairing with a short courtship, and larvae that swim at the surface and seek cover in the meniscus of floating objects when predators attack.
Females ready to release eggs have been found from September to January. Spent fish (examination of the ovaries indicates that only a small percentage of eggs are sufficiently developed to the stage at which they are able to be fertilised) have been collected from November to April. The number of spent males and females was found to be highest in January. This indicates that honey blue-eyes begin to spawn in the wild as early as September/October and that most members of the population have ceased to spawn by January-February. Spawning in the wild occurs at temperatures in the range of 26-28°C. Females spawn at around 17-22 mm in size with the larger females producing more eggs than smaller females.
Source
Allen, G.R. and Ivantsoff, W. (1982). Pseudomugil mellis, Le Honey Blue-eye, une nouvelle espece de Poisson Arc-en-ciel (Melanotaeniidae) d'Australie orientale. Revue francaise Aquariologie 9(3): 83-86.
Arthington, A.H. and Marshall, C.J. (1993). Volume 1: Distribution, ecology and conservation of the Honey Blue-eye, Pseudomugil mellis, in south-eastern Queensland. Final Report to the Australian Nature Conservation Agency, Canberra. 100 pp.
Arthington, A.H. Marshall, C.J. (1995). Threatened fishes of the world: Pseudomugil mellis Allen & Ivantsoff, 1982 (Pseudomugilidae). Environmental Biology of Fishes 43: 268.
Burnett Mary Natural Resource Management Plan (2005). Country to Coast - A Healthy Sustainable Future. Burnett Mary Regional Group.
Howe, E. (1987). Breeding behaviour, egg surface morphology and embryonic development in four Australian species of the genus Pseudomugil (Pisces: Melanotaenidae) in Australian Journal of Marine and Freshwater Research 38: 885-895
Howe, E., C. Howe & S. Doyle (1988). The surface of the egg in blue eyes in Fishes of Sahul 5(2): 205-211.
Saeed, B., Ivantsoff, W., and Allen, G.R. (1989). Taxonomic revision of the family Pseudomugilidae (Order Atheriniformes). Australian Journal of Marine and Freshwater Research 40: 719-787.
Semple, G.P. (1991), Reproductive Behaviour and early Development of the Honey Blue-eye, Pseudomugil mellis Allen and Ivantsoff 1982 (Pisces: Pseudomugilidae), from the North-east Coast Division, South-eastern Queensland, Australia. Australian Journal of Marine and Freshwater Research 42: 277-286.
Tappin, A.R. (1984) In search of the Honey Blue eye, Pseudomugil mellis. Fishes of Sahul 1(4): 37-39.
Trnski, T., D.J. Bray, J.M. Leis, M.A. McGrouther & S.E. Reader (1993) Survey of Fishes of Shoalwater Bay Training Area, Queensland.
Wager, R. and Jackson, P. (1993). The Action Plan for Australian Freshwater Fishes. Australian Nature Conservation Agency, Canberra.
© Copyright Adrian R. Tappin
Updated February, 2007.
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