Considered part of the Mountain galaxias complex since the early 1980s, Ornate galaxias was reinstated as a distinct species in 2014. Maximum size 110 mm Length to Caudal Fork (LCF), but commonly 55–75 mm LCF. A moderate-size galaxias with the characteristic galaxiid elongate body shape, slightly laterally compressed. The dorsal fin base is slightly shorter than anal fin base, with both of these fins rounded and of moderate length. The anal fin is a little longer than the dorsal, and anal fin origin usually originates at or behind the middle of the dorsal fin base. Caudal fin is of moderate length, slightly forked, about same length as the caudal peduncle.
Body is predominantly light brown or brown on back and sides, with small to moderate-sized, closely spaced, brown to grey-brown, irregular shaped blotches, and patches which often fuse to form irregularly shaped vertical bands. These bands and blotches are densely distributed over the back, top and sides of head, and extend down the sides reaching well below the lateral line. The belly is creamy white; the mouth is terminal, of moderate length, usually reaching to under middle of eye.
Much of the ecology of this species has been described as part of studies on Mountain galaxias (with which it was formerly included). It is a species that can survive in a range of habitats; from ephemeral lowland streams where it can occur in isolated and sometimes stagnant pools, to cool, clear, shaded, small mountain creeks and moist gullies. It is often found in habitats with good instream cover (rock, large and small woody habitat, aquatic vegetation, and undercut banks).
Sexual maturity can be reached in the first year and at a relatively small size: 42 mm LCF for males and 47 mm LCF for females; with all fish sexually mature in their second year. Spawning has been recorded from June-October, and it is unknown whether this indicates a long spawning season, or flexibility between years depending on environmental conditions. Fecundity is moderate to high, with 492 eggs recorded from a 66 mm fish.
Spawning site characteristics of this species are similar to that described for the Barred galaxias, with both species laying small numbers of relatively large, adhesive eggs, predominantly in riffles. The eggs are laid on the downstream side of cobbles or boulders where water flows provides good oxygenation. Newly hatched larvae are approximately 9.5 mm long, absorb their yolk sac after 5 days and commence feeding by 8 days after hatching.
Like the Mountain Galaxias and Climbing galaxias, the species may be potentially good at climbing over wet rocks.
The diet has not been studied in the only MDB population (Yea River drainage) but diet in the in the intermittent Lerderderg River in Vic consisted predominantly of dipteran larvae (particularly midges) and terrestrial invertebrates that fall on the water surface. There was some variability in the diet between low flows in April and high flows in September, with the high flow diet containing more stoneflies, caddisflies and some fish eggs. Feeding activity was also noticeably higher during high flow, particularly at dusk.
Movement requirements are unknown, but the species is thought to be non-migratory and relatively sedentary, as for most other species in the Mountain galaxias complex.
This species generally occurs in coastal streams south of the Great Dividing Range in coastal Victoria between Wilsons Promontory and Cape Otway. A small population is also present within the MDB, in Hirts Creek, upstream of a waterfall in the upper reaches of the Yea River drainage in the Goulburn River catchment. This isolated population is only known from above a waterfall and has not been found downstream where alien Brown trout are abundant. It is unknown whether this population is a natural remnant population of the MDB; a natural dispersal event across the dividing range; or is the result of a translocation (possibly as bait fish; see Spotted galaxias).
Like many species in the Mountain galaxias complex, the Ornate galaxias is often found with small grey to black cysts visible in the flesh, and these are probably the metacercariae of trematode parasites. No individuals have been recorded from the Sustainable Rivers Audit (2004–2013) or the MDB Fish Survey (2014/15–2021/22).
Interaction with Rainbow and Brown trout (largely via predation) is the major threat to some populations, but in intermittent streams it appears able to coexist in the presence of trout (where high water temperatures disadvantage trout). Within its coastal range, major threats are decline of quality and quantity of habitat as a result of urbanisation and agricultural development. Climate change impacts (droughts, bushfires, storms) will exacerbate habitat decline, and population fragmentation from artificial instream barriers and water extraction are also threats.
Closs 1994; Closs & Lake 1996; O’Connor & Koehn 1991; Raadik 2011, 2014, 2019d.
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