NATIVE SPECIES
Mountain galaxias (Ornate mountain galaxias)
Scientific Name
Galaxias olidus Günther, 1866
Declining
Photo: Gunther Schmida
Common Name
Identification
A small, elongate, tubular fish. Maximum
size 140 mm; average 70–80 mm. The body
patterning is variable, with stripes, blotches
or no markings present. The back is usually
brownish to yellowish-green, and the belly is
olive to silvery white. Scales are absent, the
tail is truncate to weakly forked, and the anal
fin originates at or behind the middle of the
dorsal fin.
The Mountain galaxias is quite a variable
small fish, with several former species of
Galaxias subsumed into Galaxias olidus in
the early 1980s. However, it is likely that
some of these species may be reinstated in the
near future, and new ones, such as the Riffle
galaxias and Obscure galaxias, described.
Biology and Habitat
Mountain galaxias are found in a variety of
habitats from small creeks to large rivers.
They are often observed in schools in slower
flowing or pool habitats, but in situations
where trout are abundant they may be
restricted to very shallow edge habitats or
44
riffles. They occur at a variety of altitudes
within the Murray-Darling Basin, and are the
only native fish that is found in the alpine
zone above the snowline during winter.
Individuals mature at the end of their first
year or in their second year. Spawning occurs
mainly in spring and early summer although
a small proportion of fish may spawn in
autumn. Between 50 and 400 eggs are laid on
the underside of stones at the head of pools
and in riffles. Eggs are approximately 2.5 mm
in diameter and hatch in about three weeks.
Larvae are about 10 mm long at hatching.
The species is thought not to migrate, and to
have a relatively small home range of around
19 m. It has been recorded basking on damp
rocks in alpine areas. The diet consists mainly
of aquatic insect larvae, but terrestrial insects
that fall onto the water from overhanging
vegetation may form a substantial part of the
diet.
Distribution and Abundance
Mountain galaxias are widely distributed
throughout south-eastern Australia, from
F i s h e s o f t h e M u r r ay- D a r l i n g B a s i n
ID Valley
1 Avoca
2 Border Rivers
3 Broken
4Campaspe
5Castlereagh
6Central Murray
7Condamine
8Darling
9Goulburn
10Gwydir
11 Kiewa
12 Lachlan
13 Loddon
14 Lower Murray
15 Macquarie
16 Mitta Mitta
17 Murrumbidgee
18Namoi
19Ovens
20 Paroo
21Upper Murray
22 Warrego
23 Wimmera
southern Qld through to SA. They are not
restricted to the mountains, being found
in lowland habitats as well. However, other
galaxiids such as the Common galaxias are
more abundant and widespread in lowland
rivers in the Basin.
As with other galaxiid species, where trout are
present the abundance of Mountain galaxias
is greatly reduced in lowland streams and
eliminated from many upland streams. In
such situations galaxiids are only found above
waterfalls or swamps that prevent trout access.
An experiment to remove Rainbow trout
from a section of Lees Creek in the ACT has
resulted in the recolonisation by galaxiids of
the trout-free section of stream.
Infection with the alien parasitic copepod
Lernaea has been shown to cause significant
mortality.
General References
Berra 1973; Bond 2004; Cadwallader et al.
1980; Green 1979; Lintermans 2000, 2002;
McDowall 2006; McDowall & Fulton 1996;
O’Connor & Koehn 1991; Raadik 2001.
Potential Threats
Continued spread of alien species, particularly
trout, threatens local galaxiid populations.
The effects of the Climbing galaxias—which
have been transferred to inland waters via
the Snowy Mountains Scheme—on natural
galaxiid populations is unknown, but
competition or displacement is possible.
An introductory guide
45
Published by the Murray-Darling Basin Commission
Postal address: GPO Box 409, Canberra ACT 2601
Office location: Level 3, 51 Allara Street, Canberra City ACT
Telephone: (02) 6279 0100, international + 61 2 6279 0100
Facsimile: (02) 6248 8053, international + 61 2 6248 8053
Email: [email protected]
Internet: http://www.mdbc.gov.au
For further information contact the Murray-Darling Basin Commission office on
(02) 6279 0100
This fish fact sheet is an extract derived from the report:
Lintermans, M. 2007, Fishes of the Murray-Darling Basin: An introductory guide.
MDBC Publication No. 10/07
ISBN 1 921257 20 2
© Murray-Darling Basin Commission 2007
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F i s h e s o f t h e M u r r ay- D a r l i n g B a s i n