Not furry, but we like them anyway.
Murray River Rainbowfish
Melanotaenia fluviatilis (Castelnau, 1878)
Also called Australian rainbowfish
From South-eastern Australia, west of the Great Dividing Range: the Murray-Darling basin in New South Wales, southern Queensland and northern Victoria.123
At a glance the quick version
FishBase: males up to 11 cm SL, females 7 cm SL; Seriously Fish gives 10 cm SL
Looks how to spot one
Scaled, elongated rainbowfish
A slim-bodied fish with a small head, large eyes, two dorsal fins and a lightly forked tail. The sides are silvery-brown with a green or silver sheen and a blue line from snout to tail. Males have orange stripes and red-spotted fins and grow a higher back; females are paler.12
Personality what they are like
A very peaceful schooling fish that suits a community of similar-sized species. Males show their best colours when other males are around.21
Daily activity how busy a day looks
An active swimmer that needs open space; Seriously Fish rates it easy, with space as the main requirement.2
Grooming and care the hands-on bits
Give plenty of plants and swimming room and a varied diet. Unlike most rainbowfish it can live in an unheated tank or a temperate outdoor pond in summer.23
Home where they are happiest
Minimum tank base about 90 x 30 cm (around 81 litres). Temperature 20-25 °C (it tolerates 10-15 °C in winter but is less active), pH 6.5-8.0, hardness 8-20 dGH.231
Food basics what goes in the bowl
Omnivore. Wild fish eat aquatic and land invertebrates and filamentous algae; in the aquarium it takes flakes, frozen and live foods.12
Company who they like around
Keep a group of at least 6-8; a larger group gives the best display.21
The story where it all began
Castelnau described it in 1878. For a long time it was lumped with the crimson-spotted rainbowfish or the eastern rainbowfish, until genetic and body-measurement differences led to it being recognised as its own species in 1986.12
Fun facts for the dinner table
- 1
It is the most southerly ranging rainbowfish in the world.3
- 2
It is the only rainbowfish adapted to cold winters, coping with water around 10-15 °C.3
- 3
FishBase notes its potential for outdoor pond keeping in temperate climates.3
- 4
Northern and southern populations differ in how they handle temperature.2
Recognised by the official bits
- IUCN Red List
- Least Concern (assessed February 2019)3
- Taxonomy
- Family Melanotaeniidae; described by Castelnau in 1878 as Aristeus fluviatilis; recognised as a separate species in 19861
The care rhythm Furry Diary remembers it for you
A typical home-care rhythm for a Murray River Rainbowfish. It is our own starting plan, not a vet's advice, and you can change every line in the app.
- FeedingSmall amounts once or twice a dayevery day
- Temperature checkevery day
- Water changeAbout 25% of the waterevery week
- Water testevery week
- Glass cleanevery week
- Filter rinseRinse in old tank water, never tap waterevery month
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Pacific Blue-eyeLike what we are building? Buy Archy a bone.
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Where this comes from
Every breed page shows where each fact comes from. If we got something wrong, sorry, we are pet people, not a science magazine. Tell us at support@furrydiary.app and we will fix it.
- Wikipedia: Murray River rainbowfish en.wikipedia.orgused for other names, distribution, description, taxonomy history, diet
- Seriously Fish: Melanotaenia fluviatilis (Murray River Rainbowfish) seriouslyfish.comused for habitat, size, tank size, water parameters, diet, behaviour, group size, dimorphism
- FishBase: Melanotaenia fluviatilis, Murray River rainbowfish fishbase.seused for author and year, max length by sex, water ranges, IUCN status, cold tolerance, pond use
Checked 2026-09-30. Text is written in our own words from these sources.