Cairns rainbowfish
Cairnsichthys rhombosomoides
Adult needs, habitat, social behaviour and care sources for this fish.
At a glance
Welfare notes
- This is a social species. Keep in groups of at least 6; smaller groups cause chronic stress.
- Native habitat: flowing_stream.
- Australian native. Collection and keeping rules vary by state and territory.
Where this care information comes from
Confidence: unreviewed · reviewed 9/20/2026
Seriously Fish husbandry; FishBase size and rangeSame-species strategy: shoal
Wild collection is limited to permitted areas of far north Queensland.
Australia reference notes
Import rules and the rules for keeping a fish are not always the same.
- Federal import
- Import status not yet verified
- Keeping this species
- Check state or territory rules
- Evidence confidence
- Incomplete. Check the current rules before relying on this.
- Last reviewed
- Not recorded
We still need to add a source for this jurisdiction.
These notes only cover Australia and may not apply where you live. Rules can also change, so check with your local fisheries or wildlife authority before buying, moving or collecting fish.
How FishTankr checks this fish
This fish affects tank mates, swimming room and water. The cycle can limit the score. Waste load and biotope match stay separate.
Species compatibility
This is a peaceful fish with no known fin-nipping or predation risks. It may suit similarly sized community fish, but check the full group in the builder.
Waste load (beta)
Each Cairns rainbowfish adds about 1.6 to our early-stage waste estimate. We only use this to show a broad beta band. It does not set a safe fish limit, and a faster pump cannot improve it.
Space to swim
This fish needs at least 100 L for adult swimming and territory. It is an active swimmer, so tank length matters as much as volume.
Biotope match
This fish comes from Australian native (flowing_stream), where the pH is typically 6–7.5 and the temperature 20–26 °C. The optional biotope match looks for fish, water and décor from the same region.
Regional reference
This fish is native to Australia. Rules for collecting, importing and keeping it vary by region, so check your local guidance before buying.
Where to buy
We do not track shop stock. Pick your location and we will run a live search for Cairns rainbowfish on each independent shop's own website.
Search links go straight to each shop's own site, so you always see their current stock, not our copy of it. Delivery details show the date we last checked them on the shop's site.
Related species
These fish have promising swim-zone, temperament and water matches. Add the full group to your tank plan before deciding whether they can live together.
Individual fish vary. Check each species’ needs and local regulations before you buy.