NATIVE SPECIES

Common Name Murray-Darling Uncommon (Crimson-, Murray River rainbowfish)

Scientific Name fluviatilis( Castelnau, 1878) Photo: Gunther Schmida

Male in breeding colouration

Identification Biology and Habitat A small, strongly laterally compressed , Rainbowfish are a tropical to sub-tropical the adults of which have a relatively deep group, and Murray-Darling rainbowfish is body. Maximum length 90 mm, commonly the southern-most species in the group. The less than 70 mm. The eyes are large and species is generally found in the lowland parts positioned towards the top of the head, and of the Basin, and prefers slow-flowing rivers, the mouth is moderately large, oblique and wetlands and billabongs. It is a schooling upturned, with several rows of small, conical species—schools of 30 or more are commonly teeth. There are two dorsal fins separated by seen swimming just below the water surface. a small gap, with the first short-based and Breeding is seasonal, generally spring-summer the second long-based. There is a long-based when water temperature exceeds 20°C, and anal fin and the tail is moderately forked. males perform an elaborate courtship display. There is no lateral line and the scales are Fecundity is low (average 130 eggs, range 35– relatively large. Colouration varies with sex, 333) with females laying 5–20 eggs per batch, age and habitat, but is generally silvery with in 3–4 batches per day for several days. The a greenish iridescence and whitish on the eggs sink and lodge amongst aquatic plants, lower head and belly. Younger individuals where they attach via adhesive threads. Eggs are translucent. The majority of scales have a are 1.3–1.8 mm diameter, and hatch after brownish margin. There is a pink to-reddish about 1 week, with the larvae ~2.0–3.7 mm spot on the operculum. Males have red spots long. Individuals mature at 10–12 months on the dorsal, caudal and anal fins, and the old. Until recently it was not known that this fins of breeding males have a blackish margin. species migrated, but individuals as small as Females and immatures have clear fins. 21 mm have been recorded moving through a fishway on the Murrumbidgee River, most commonly in the afternoon and dusk.

66 of the Murray-Darling Basin An introductory guide 67 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

The species is carnivorous, consuming aquatic Potential Threats invertebrates as well as terrestrial invertebrates Predation of adults by Redfin perch and larvae that fall on the water surface. Some by Eastern gambusia are considered potential filamentous algae is also consumed. threats, as are loss of aquatic vegetation (spawning sites and cover) and cold-water Distribution and Abundance pollution. Formerly widespread across the Basin, the Murray-Darling rainbowfish has declined General References in the Murray region, but is still patchily Backhouse & Frusher 1980; Baumgartner recorded from the middle and lower sections 2003; Cadwallader & Backhouse 1983; of the Murray, Murrumbidgee and Macquarie Humphries et al. 2002; Koehn & O’Connor rivers, and parts of the Gwydir, Namoi and 1990; Lloyd & Walker 1986; McGuigan et al. Bogan rivers in NSW. In Vic, cold winter 2000; Milton & Arthington 1984; Moffat & temperatures limit it to the Murray and its Voller 2002; Wedderburn & Hammer 2003. tributaries such as the Goulburn and Broken rivers. The species is not present in the relatively upland ACT, and appears to have disappeared from the Lower Lakes in SA. It is still common but localised/patchy in wetlands and vegetated edges of the main channel of the Lower Murray River in SA and the lower Victorian section below the Darling junction. It appears to be common in the Qld portion of the Basin, but may be confused with the Desert rainbowfish.

66 Fishes of the Murray-Darling Basin An introductory guide 67 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 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.

ii Fishes of the Murray-Darling Basin