Ambassis macleayi, commonly known as Macleay's glassfish, Macleay's glass perchlet, Macleay's perchlet, reticulated glassfish, reticulated perchlet, or network perchlet, is a species of freshwater fish in the family Ambassidae. It is native to northern Australia and the trans-Fly River region of New Guinea. It is a fish with a vertically flat, narrow body and a standard length generally between , with large specimens reaching long. It generally eats water fleas and other small invertebrates. This fish is considered to be a least-concern species according to the International Union for Conservation of Nature (IUCN), although it could suffer from habitat degradation due to feral pigs and invasive water plants such as the water hyacinth. The fish is suitable for aquarium use in tanks containing other non-aggressive species.
Taxonomy
French naturalist Francis de Castelnau described this species as Pseudoambassis macleayi in 1878, from specimens collected from the Norman River near the Gulf of Carpentaria in northern Australia. The species was named in honour of William Macleay for his important contributions to fish taxonomy. Castelnau placed it in a new genus, separate to Ambassis, due to its lack of a recumbent spine (spine laying against the dorsal surface) in front of its dorsal fin. Allan Riverstone McCulloch placed it in the genus Ambassis in 1929. Gilbert Percy Whitley made it the type species of the genus Austrochanda, calling it Austrochanda macleayi, in 1935. The species was subsequently returned to Ambassis in 1989 by J. R. Paxton, D. F. Hoese, G. R. Allen, and J. E. Hanley in the Zoological Catalogue of Australia. Common names include Macleay's glassfish, Macleay's glass perchlet, Macleay's perchlet and reticulated glassfish.
Description
Macleay's glassfish is a moderately large ambassid that may grow to a standard length (SL) of , but is usually between . Males tend to be larger than females. The body is deep, at close to half the SL, with a large head and a maxilla (upper jaw) that extends beyond the front edge of the large eye. The first dorsal fin is tall at up to 40% SL, with the second spine longer than the first; within the anal fin, the third spine is longer than the second. Colour varies from a partly transparent olive-green to a dark brown/green or a golden/yellow, with the lower surfaces generally paler. Scales have a darker edge giving a reticulated pattern, especially on the upper half. The caudal (tail), anal and dorsal fins are dusky with off-white to translucent spines and white to yellow rays; the caudal and anal fins may have a thin reddish or dark margin; pelvic fins are white and the pectoral fins are transparent often with a dark mark at the base of the fin. A. macleayi may be differentiated from other fish of the genus Ambassis by the relatively deep body, high gill raker count, interrupted lateral line and the dark spot at the base of the pectoral fins.
Distribution and habitat
Ambassis macleayi occurs from the Carson River in the Kimberley region of Western Australia across the north of Australia to the Jardine River in Cape York, although the distribution in north-east Queensland is patchy. In New Guinea, the fish is found in the trans-Fly region, a lowland area of savanna and grasslands in the south of the island.
Preferred habitat consists of streams and swamps, tending towards muddy lagoons at the end of the dry season to much further afield by the end of the wet season including lowland lagoons and the main channel of rivers and streams in the escarpments surrounding the Gulf of Carpentaria. It is typically found in heavily vegetated habitats with macrophytes, woody debris and leaf-litter and rarely at a depth of more than 1 m (3 ft). The fish is found in less vegetated water than other species of this genus and shows a preference for submerged rather than emergent vegetation. It has been found over all substrates, most commonly sand and mud then clay, gravel, leaves, rocks and boulders.
Despite high levels of connectivity during the wet season, very little dispersion of A. macleayi occurs between adjacent catchments. This has been backed up by studies showing a high degree of genetic diversity between catchments. As a result, this species is unable to rapidly recolonise areas after a disturbance and it has been recommended that any conservation of the species should be on a catchment-by-catchment basis rather than across its entire range.