F i s h e s o F t h e M u r r ay- Da r l i n g B a s i n 45An introductory guide44 F i s h e s o F t h e M u r r ay- Da r l i n g B a s i n 45An introductory guide4444 F i s h e s o F t h e M u r r ay- Da r l i n g B a s i n

identificationA 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 habitatMountain 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

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 abundanceMountain galaxias are widely distributed throughout south-eastern Australia, from

Common name Mountain galaxias (ornate mountain galaxias) Declining

scientific name Galaxias olidus günther, 1866

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F i s h e s o F t h e M u r r ay- Da r l i n g B a s i n 45An introductory guide44 F i s h e s o F t h e M u r r ay- Da r l i n g B a s i n 45An introductory guide44 An introductory guide 45

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.

Potential threatsContinued 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.

Infection with the alien parasitic copepod Lernaea has been shown to cause significant mortality.

general referencesBerra 1973; Bond 2004; Cadwallader et al. 1980; Green 1979; Lintermans 2000, 2002; McDowall 2006; McDowall & Fulton 1996; O’Connor & Koehn 1991; Raadik 2001.

iD VALLey 1 Avoca 2 Border rivers 3 Broken 4 campaspe 5 castlereagh 6 central Murray 7 condamine 8 darling 9 goulburn 10 gwydir 11 Kiewa 12 Lachlan 13 Loddon 14 Lower Murray 15 Macquarie 16 Mitta Mitta 17 Murrumbidgee 18 namoi 19 ovens 20 Paroo 21 upper Murray 22 Warrego 23 Wimmera

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: info@mdbc.gov.au 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

This work is copyright. Graphical and textual information in the work (with the exception of photographs, artwork and the MDBC logo) may be stored, retrieved and reproduced in whole or in part provided the information is not sold or used for commercial benefit and its source (Fishes of the Murray-Darling Basin) is acknowledged. Such reproduction includes fair dealing for the purpose of private study, research, criticism or review as permitted under the Copyright Act 1968. Reproduction for other purposes is prohibited without the permission of the Murray-Darling Basin Commission or the individual photographers and artists with whom copyright applies.

To extent permitted by law, the copyright holders (including its employees and consultants) exclude all liability to any person for any consequences, including but not limited to all losses, damages, costs, expenses and any other compensation, arising directly or indirectly from using this report (in part or whole) and any information or material contained in it.

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